Amidine catalyst for curable compositions

ABSTRACT

The present invention relates to an amidine of the formula (I) and its use as a catalyst for crosslinking a curable composition. The amidine of the formula (I) contains at least one aliphatic amidine group. It is substantially odorless and nonvolatile at room temperature and accelerates the crosslinking of curable compositions very efficiently, without impairing the storage stability of the compositions. It is particularly suitable for compositions based on polymers containing silane groups, with which it is compatible, as a result of which such compositions do not have a tendency to separation or migration or evaporation of the catalyst.

This is a Divisional of application Ser. No. 15/580,967 filed Dec. 8,2017, which is a National Stage Application of PCT/EP2016/064303 filedJun. 21, 2016, which in turn claims priority to European Application No.15173193.2 filed Jun. 22, 2015. The entire disclosures of the priorapplications are hereby incorporated by reference herein their entirety.

TECHNICAL FIELD

The invention relates to amidines and to the use thereof as catalystsfor curable compositions.

STATE OF THE ART

Curable compositions play a significant role in many industrialapplications, for example as adhesives, sealants or coatings. The curingthereof is brought about by crosslinking reactions which proceed viafree or latent reactive groups, for example isocyanate groups, epoxidegroups, hydroxyl groups, amino groups or silane groups, wherein thesereact with themselves or one another following a mixing operation orthrough heating or through contact with moisture, and hence bind theformation components present in the composition covalently to form apolymeric network. Acceleration of such crosslinking reactions isfrequently accomplished using catalysts. These are very often substancesof toxicological concern which constitute a potential hazard to usersand the environment, especially after the curing of the composition, ifthe catalyst or degradation products thereof are released by outgassing,migration or washing-out.

Compositions curable at room temperature that are based on polymerscontaining silane groups are confronted with this problem to asignificant degree. Polymers containing silane groups here areespecially polyorganosiloxanes, which are commonly referred to as“silicones” or “silicone rubbers”, and organic polymers containingsilane groups, which are also referred to as “silane-functionalpolymers”, “silane-modified polymers” (SMP) or “silane-terminatedpolymers” (STP). The crosslinking thereof proceeds via the condensationof silanol groups to form siloxane bonds and is conventionally catalyzedby means of organotin compounds such as dialkyltin(IV) carboxylates inparticular. These are notable for very high activity in relation to thesilanol condensation and are very hydrolysis-resistant, but they areharmful to health and a severe water pollution hazard. They are oftencombined with further catalysts, mainly basic compounds, such as aminesin particular, which specifically accelerate the preceding hydrolysis ofthe silane groups.

Because greater weight is being given to EHS aspects by professionalorganizations and users and because of stricter government regulation,there have been increased efforts for some time to replace organotincompounds with other catalysts of lower toxicity. For instance,organotitanates, -zirconates and -aluminates have been described asalternative metal catalysts. However, these usually have lower catalyticactivity in relation to the silanol condensation and bring about muchslower crosslinking. Because of their lack of hydrolysis stability, theycan lose a large part of their activity in the course of storage of thecomposition as a result of residual moisture in the ingredients, whichcauses the curing to slow significantly or stop entirely.

A further known alternative to organotin compounds is highly basicnitrogen compounds from the class of the amidines and guanidines, whichcan be used in combination with the metal catalysts mentioned or elsealone. However, many of the commonly used amidine and guanidinecatalysts, such as, in particular, 1,8-diazabicyclo[5.4.0]undec-7-ene(DBU) and 1,1,3,3-tetramethylguanidine (TMG), are volatile and odoroussubstances that are likewise harmful to health and hazardous to theenvironment. Moreover, they have a tendency to migrate because of lowcompatibility in the composition and hence to cause separation,exudation or substrate soiling. The described use of aromatic amidinesand guanidines that are solid at room temperature provides a remedyhere, but requires the use of suitable solvents and brings losses incatalytic activity and hence crosslinking rate.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a catalystfor the crosslinking of curable compositions, especially compositionscontaining silane groups, which has a high catalytic activity for thecrosslinking reaction and hence enables rapid curing of the compositionapplied, and also has a high selectivity for this crosslinking reactionand hence does not unduly impair the storage stability of thecomposition. Furthermore, the catalyst is to have a low vapor pressureand high compatibility with the composition, such that it has notendency either to separate or migrate or to evaporate, and is to haveminimum odor and low toxicity.

This object is achieved by an amidine of the formula (I) as described inclaim 1. The amidine of the formula (I) contains at least one aliphaticamidine group. It has only low or zero volatility and exhibits highactivity when used as a catalyst for curable compositions, whereasaromatic amidines have barely any or zero catalytic activity. Bycontrast with many catalysts having aliphatic amidine or guanidinegroups that are known from the prior art, the amidine of the formula (I)is substantially odorless and nonvolatile at room temperature. Itexhibits high catalytic activity coupled with good selectivity,especially in compositions based on polymers containing silane groups.This is particularly surprising, given that, on the basis of itsrelatively high molecular weight and the strong intermolecularinteractions via hydrogen bonds, reduced activity would be expected ascompared with smaller, less polar and hence more mobile amidines.

With these properties, the amidine of the formula (I) is particularlysuitable for use in compositions based on polymers containing silanegroups, where, as sole catalyst or in combination with furthercatalysts, it enables rapid curing to give a mechanically high-qualityand durable material, without impairing the storability of the uncuredcomposition. Both before and after curing, it has excellentcompatibility with the composition and does not have any tendency eitherto separate or to migrate, by contrast with many similar compositionscomprising amidine or guanidine catalysts according to the prior art,where catalyst-related migration effects play a major role. It enableslow-emission and low-odor products which have neither greasy nor tackysurfaces, nor do they cause substrate soiling. Finally, the amidine ofthe formula (I) is preparable in a surprisingly simple process withoutauxiliaries from commercially available, inexpensive starting materials.

Further aspects of the invention are the subject of further independentclaims. Particularly preferred embodiments of the invention are thesubject of the dependent claims.

Ways of Executing the Invention

The invention provides an amidine of the formula (I)

where

p is an integer from 1 to 6 and r is an integer from 0 to 5, where (p+r)is an integer from 1 to 6,

L is

-   -   a (p+r)-valent hydrocarbyl radical having an average molecular        weight in the range from 15 to 20,000 g/mol, optionally having        heteroatoms, especially oxygen or nitrogen or silicon in the        form of ether, tertiary amino, ester, amide, urethane, urea,        uretdione, isocyanurate, biuret, allophanate, uretonimine,        iminooxadiazinedione, oxadiazinetrione or alkoxysilane groups,        or, in the case that r=0 and p=1, may also be a hydrogen        radical,

Q is a reactive group selected from glycidoxy, N-aziridinyl,(meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, maleate,maleamide, maleimide, fumarate, fumaramide, itaconate, itaconamide,crotonate and crotonamide,

Q′ is a divalent connecting unit formed from the reaction of a reactiveQ group with HZ, and

Z is an aliphatic amidine group bonded via a nitrogen atom, where everyZ is separated from every other Z by at least 2 carbon atoms, and where,in the case that r=0 and p=1 and of (meth)acrylamide or maleamide orfumaramide or itaconamide or crotonamide as reactive Q group, L and Q′may also together be a monovalent hydrocarbyl radical having 5 to 20carbon atoms and having heteroatoms in the form of amide groups andoptionally ether or ester groups.

In the present document, the term “aliphatic amidine group” refers to anamidine group which does not contain any nitrogen atom which is bondeddirectly to an aromatic ring or is part of a heteroaromatic ring system,for example imidazole or pyrimidine.

“Primary amino group” and “primary amine nitrogen” refer respectively toan NH₂ group and the nitrogen atom thereof that is bonded to an organicradical, and “secondary amino group” and “secondary amine nitrogen”refer respectively to an NH group and the nitrogen atom thereof that isbonded to two organic radicals which may also together be part of aring, and “tertiary amino group” and “tertiary amine nitrogen” referrespectively to an N group and the nitrogen atom thereof that is bondedto three organic radicals, two or three of which together may also bepart of one or more rings.

The term “silane group” refers to a silyl group which is bonded to anorganic radical or to a polyorganosiloxane radical and has one to three,especially two or three, hydrolyzable substituents on the silicon atom.Particularly useful hydrolyzable substituents are alkoxy radicals. Thesesilane groups are also referred to as “alkoxysilane groups”. Silanegroups may also be in partly or fully hydrolyzed form.

“Hydroxysilane”, “isocyanatosilane”, “aminosilane” and “mercaptosilane”refer respectively to organoalkoxysilanes having one or more hydroxyl,isocyanato, amino or mercapto groups on the organic radical in additionto the silane group.

Substance names beginning with “poly”, such as polyol or polyisocyanate,refer to substances containing, in a formal sense, two or more of thefunctional groups that occur in their name per molecule.

The term “organic polymer” encompasses a collective of macromoleculesthat are chemically homogeneous but differ in relation to degree ofpolymerization, molar mass and chain length, which has been prepared bya poly reaction (polymerization, polyaddition, polycondensation) and hasa majority of carbon atoms in the polymer backbone, and reactionproducts of such a collective of macromolecules. Polymers having apolyorganosiloxane backbone (commonly referred to as “silicones”) arenot organic polymers in the context of the present document.

The term “polyether containing silane groups” also encompasses organicpolymers which contain silane groups and which, in addition to polyetherunits, may also contain urethane groups, urea groups or thiourethanegroups. Such polyethers containing silane groups may also be referred toas “polyurethanes containing silane groups”.

“Molecular weight” is understood in the present document to mean themolar mass (in grams per mole) of a molecule or part of a molecule, alsoreferred to as “radical”. “Average molecular weight” is understood tomean the number-average M_(n) of an oligomeric or polymeric mixture ofmolecules or radicals, which is typically determined by means of gelpermeation chromatography (GPC) against polystyrene as standard.

“Storage-stable” or “storable” refers to a substance or composition whenit can be stored at room temperature in a suitable container over aprolonged period, typically at least 3 months up to 6 months or more,without any change in its application or use properties, especially inthe viscosity and crosslinking rate, to a degree of relevance for theuse thereof as a result of the storage.

A dotted line in the formulae in this document in each case representsthe bond between a substituent and the corresponding molecular radical.

“Room temperature” refers to a temperature of about 23° C.

Preferably, Z is

where

R¹ where

R¹ is a hydrogen radical or an alkyl or cycloalkyl or aralkyl radicalhaving 1 to 8 carbon atoms or together with R² is R⁴,

R² is a hydrogen radical or an alkyl, cycloalkyl or aralkyl radicalwhich has 1 to 18 carbon atoms and optionally contains ether oxygen ortertiary amine nitrogen, or together with R¹ is R⁴,

R³ is a hydrogen radical or an alkyl or cycloalkyl or aralkyl radicalhaving 1 to 12 carbon atoms,

where R⁴ is an optionally substituted 1,2-ethylene, 1,3-propylene or1,4-butylene radical having 2 to 12 carbon atoms,

and where

R² and R³ together may also be an alkylene radical having 3 to 6 carbonatoms.

R¹ is preferably an alkyl or cycloalkyl or aralkyl radical having 1 to 4carbon atoms or together with R² is R⁴.

R² is preferably an alkyl, cycloalkyl or aralkyl radical which has 1 to12, especially 1 to 8, carbon atoms and optionally contains ether oxygenor tertiary amine nitrogen, or together with R¹ is R⁴.

R³ is preferably a hydrogen radical or an alkyl, cycloalkyl or aralkylradical having 1 to 8, especially 1 to 4, carbon atoms.

R³ is more preferably a hydrogen radical or methyl radical, mostpreferably a methyl radical.

More preferably, R¹ and R² together are R⁴.

More preferably, Z thus has the formula

Such an amidine of the formula (I) is preparable in a particularlysimple manner and in high purity.

R⁴ preferably has 2 to 6 carbon atoms.

R⁴ is preferably 1,2-ethylene, 1,2-propylene, 1,3-propylene,2-methyl-1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,3-butylene,1,4-butylene, 1,3-pentylene, 1,2-cyclohexylene, 1,3-cyclohexylene or2(4)-methyl-1,3-cyclohexylene.

R⁴ is more preferably 1,2-ethylene, 1,2-propylene, 1,3-propylene,2-methyl-1,2-propylene, 2,2-dimethyl-1,3-propylene, 1,3-butylene or1,3-pentylene, especially 1,2-ethylene or 1,3-propylene.

Most preferably, R⁴ is 1,3-propylene.

More preferably, R³ is methyl and R⁴ is 1,3-propylene. Such an amidinehas particularly high catalytic activity and is preparable in aparticularly simple manner.

p is preferably 1 or 2 or 3.

r is preferably 0.

(p+r) is preferably 1 or 2 or 3.

More preferably, p is 1 or 2 or 3 and r is 0.

L is preferably a (p+r)-valent hydrocarbyl radical which has an averagemolecular weight in the range from 15 to 5,000 g/mol, especially 15 to2,000 g/mol, and optionally contains oxygen or nitrogen or silicon inthe form of ether, tertiary amino, ester, urethane, isocyanurate,biuret, allophanate or alkoxysilane groups, or is a hydrogen radical.

If Q is glycidoxy or N-aziridinyl, L is preferably not a hydrogenradical. Such an amidine of the formula (I) is free of primary hydroxylgroups and free of primary amino groups and hence is particularlystorage-stable together with silane groups and/or isocyanate groups.

Q is preferably a reactive group selected from glycidoxy, N-aziridinyl,(meth)acrylate, (meth)acrylamide, maleate, maleamide, maleimide anditaconate.

Glycidoxy is a reactive group of the formula

N-aziridinyl is a reactive group of the formula

(meth)acrylate or (meth)acrylamide or itaconate is a reactive group ofthe formula

maleate or maleamide is a reactive group of the formula

and maleimide is a reactive group of the formula

where

W is O or NR⁵, where R⁵ is a hydrogen radical or a monovalenthydrocarbyl radical having 1 to 8 carbon atoms or together with L is anoptionally substituted alkylene radical which has 2 to 6 carbon atomsand optionally contains an ether oxygen,

E¹ is a hydrogen radical or methyl radical,

E² is a hydrogen radical or methyl radical or alkoxycarbonylmethylradical having 3 to 10 carbon atoms, and

E³ is an alkyl radical having 1 to 8 carbon atoms.

R⁵ is preferably methyl, ethyl, propyl, isopropyl, butyl, tert-butyl ortogether with L is 3-oxa-1,5-pentylene.

W is preferably O.

E² is preferably a hydrogen radical or a methyl, methoxycarbonylmethyl,ethoxycarbonylmethyl or butoxycarbonylmethyl radical, especially ahydrogen radical or a methyl radical.

E³ is preferably methyl, ethyl or a butyl radical.

Q′ is preferably selected from the group consisting of

where W, E¹, E² and E³ have the definitions already given.

The letters (L) and (Z) between brackets represent the bond from Q′ to Land Z respectively.

If Q′ is

Q′ has formed from the reaction of HZ with a glycidoxy group.

L in this case is preferably a (p+r)-valent hydrocarbyl radical whichhas a molecular weight in the range from 15 to 1,500 g/mol andoptionally contains ether oxygens and optionally an alkoxysilane group,more preferably a radical selected from the group consisting of2-ethylhexyl glycidyl ether, C₈- to C₁₀-alkyl glycidyl ether, C₁₂- toC₁₄-alkyl glycidyl ether, cresyl glycidyl ether, tert-butylphenylglycidyl ether, cardanol glycidyl ether, butane-1,4-diol diglycidylether, hexane-1,6-diol diglycidyl ether, neopentyl glycol diglycidylether, polypropylene glycol diglycidyl ether having an average molecularweight in the range from 280 to 1,500 g/mol, bisphenol A diglycidylether, bisphenol F diglycidyl ether, 3-glycidoxypropyltrimethoxysilaneand 3-glycidoxypropyltriethoxysilane, in each case after removal of theglycidoxy groups.

More preferably in this case, p is 1 and r is 0 and L istriethoxysilylpropyl or trimethoxysilylpropyl. Such an amidine of theformula (I) is particularly suitable as catalyst for compositionscontaining silane groups, where it can be covalently bonded via thesilane groups in the course of curing.

If Q′ is

Q′ has formed from the reaction of HZ with an N-aziridinyl group.

L in this case is preferably a (p+r)-valent hydrocarbyl radical whichhas an average molecular weight in the range from 15 to 2,000 g/mol,especially 87 to 500 g/mol, and especially has oxygen in the form ofester groups.

If Q′ is

Q′ has formed from the reaction of HZ with a (meth)acrylate or(meth)acrylamide or itaconate or itaconamide group.

L in this case is preferably a (p+r)-valent hydrocarbyl radical whichhas an average molecular weight in the range from 15 to 5,000 g/mol,especially 15 to 2,000 g/mol, and optionally has oxygen or nitrogen orsilicon in the form of ether, tertiary amino, ester, urethane,isocyanurate, biuret, allophanate and/or alkoxysilane groups, especiallya radical selected from the group consisting of butyl, 2-ethylhexyl,trimethoxysilylpropyl, triethoxysilylpropyl, 1,2-ethylene,3,6,9-trioxa-1,11-undecylene, 2,5-dimethyl-3,6-dioxa-1,8-nonylene, apolyoxyethylene radical having a molecular weight in the range from 200to 2,000 g/mol, a polyoxypropylene radical having a molecular weight inthe range from 200 to 2,000 g/mol, 1,4-butylene, 1,6-hexylene,2,2-dimethyl-1,3-propylene, trimethylolpropane after removal of thethree hydroxyl groups, and polyurethane polymers having (meth)acrylategroups and having an average molecular weight in the range from 500 to5,000 g/mol, especially 500 to 2,000 g/mol, especially from the reactionof 2-hydroxyethyl acrylate with polyurethane polymers containingisocyanate groups.

More preferably in this case, p is 1 and r is 0 and L istriethoxysilylpropyl or trimethoxysilylpropyl. Such an amidine of theformula (I) is particularly suitable as catalyst for compositionscontaining silane groups, where it can be covalently bonded via thesilane groups in the course of curing.

If W is NR⁵, L is also preferably, together with R⁵, an optionallysubstituted alkylene radical which has 2 to 6 carbon atoms andoptionally contains an ether oxygen.

If Q′ is

Q′ has formed from the reaction of HZ with a maleate or maleamide orfumarate or fumaramide group.

L in this case is preferably a monovalent hydrocarbyl radical having 1to 8 carbon atoms, especially methyl or ethyl and butyl.

If Q′ is

Q′ has formed from the reaction of HZ with a maleimide group.

L in this case is preferably a hydrogen radical or a mono- or divalenthydrocarbyl radical having 1 to 12 carbon atoms, especially a hydrogenradical or methyl, ethyl, butyl or hexyl, or 1,2-ethylene or1,4-butylene or 1,6-hexylene.

The preferred amidines of the formula (I) are preparable from readilyobtainable starting materials in a simple process and/or haveparticularly high catalytic activity.

The amidine of the formula (I) may also be in tautomeric form. Allpossible tautomeric forms of the amidines are considered to beequivalent in the context of the present invention.

In addition, the amidine of the formula (I) may be in protonated form.

The amidine of the formula (I) may likewise be in complexed form,especially with cations of zinc, iron or molybdenum.

One example of the case that L and Q′ together are a (p+r)-valenthydrocarbyl radical which has 5 to 20 carbon atoms and has heteroatomsin the form of amide groups and optionally ether or ester groups is thereaction product shown in the formula below, formed from a cyclicamidine HZ and 4-acryloylmorpholine.

In a preferred embodiment of the invention, the amidine of the formula(I) is free of hydroxyl groups. In this case, Q is especially selectedfrom (meth)acrylate, (meth)acrylamide, (meth)acrylonitrile, maleate,maleamide, maleimide, fumarate, fumaramide, itaconate, itaconamide,crotonate and crotonamide, especially (meth)acrylate. Such an amidine ofthe formula (I) is particularly storage-stable together with silanegroups and/or isocyanate groups. It is particularly suitable as acatalyst for compositions containing silane groups or containingisocyanate groups.

In a further preferred embodiment of the invention, the amidine of theformula (I) contains a silane group. In this case, more particularly, pis 1, r is 0, L is an alkylene radical which is substituted by analkoxysilane group and has 1 to 6 carbon atoms, and Q′ is

where E⁴ is a hydrogen radical or methyl radical. Such an amidine of theformula (I) is particularly suitable as catalyst for compositionscontaining silane groups, where it can be covalently bonded via thesilane groups in the course of curing. It is especially derived from aglycidoxy-functional or a (meth)acryloyloxy-functional organosilane.

The amidine especially has the formula (I′) or the formula (I″)

where

E⁴ is a hydrogen radical or methyl radical,

E⁵ is an alkylene radical having 1 to 6 carbon atoms, especially1,3-propylene,

E⁶ is an alkyl radical having 1 to 4 carbon atoms, especially methyl orethyl, and

u is 0 or 1 and v is 2 or 3, where (u+v) is 3.

The amidine of the formula (I) is preferably obtained by the reaction of

-   -   at least one amidine of the formula HZ        with    -   at least one functional compound of the formula L        Q]_((p+r)),        where

L is

-   -   a (p+r)-valent hydrocarbyl radical having an average molecular        weight in the range from 15 to 20,000 g/mol, optionally having        heteroatoms, especially oxygen or nitrogen or silicon in the        form of ether, tertiary amino, ester, amide, urethane, urea,        uretdione, isocyanurate, biuret, allophanate, uretonimine,        iminooxadiazinedione, oxadiazinetrione or alkoxysilane groups,        or, in the case that r=0 and p=1, may also be a hydrogen        radical, or, in the case that r=0 and p=1 and of        (meth)acrylamide or maleamide or fumaramide or itaconamide or        crotonamide as reactive Q group, L and Q may also together be a        monovalent hydrocarbyl radical having 5 to 20 carbon atoms and        having heteroatoms in the form of amide groups and optionally        ether or ester groups,

and Z, Q, p and r have the definitions already given.

Preferably, L is a (p+r)-valent hydrocarbyl radical which has an averagemolecular weight in the range from 15 to 5,000 g/mol, especially 15 to2,000 g/mol, and optionally contains oxygen or nitrogen or silicon inthe form of ether, tertiary amino, ester, urethane, isocyanurate,biuret, allophanate or alkoxysilane groups, or is a hydrogen radical.

If Q is glycidoxy or N-aziridinyl, L is preferably not a hydrogenradical. Such an amidine of the formula (I) is free of primary hydroxylgroups and free of primary amino groups and hence is particularlystorage-stable together with silane groups and/or isocyanate groups.

If Q is a glycidoxy group, L is preferably a (p+r)-valent hydrocarbylradical which has a molecular weight in the range from 15 to 1,500 g/moland optionally contains ether oxygens and optionally an alkoxysilanegroup, more preferably a radical selected from the group consisting of2-ethylhexyl glycidyl ether, C₈- to C₁₀-alkyl glycidyl ether, C₁₂- toC₁₄-alkyl glycidyl ether, cresyl glycidyl ether, tert-butylphenylglycidyl ether, cardanol glycidyl ether, butane-1,4-diol diglycidylether, hexane-1,6-diol diglycidyl ether, neopentyl glycol diglycidylether, polypropylene glycol diglycidyl ether having an average molecularweight in the range from 280 to 1,500 g/mol, bisphenol A diglycidylether, bisphenol F diglycidyl ether, 3-glycidoxypropyltrimethoxysilaneand 3-glycidoxypropyltriethoxysilane, in each case after removal of theglycidoxy groups.

More preferably in this case, p is 1 and r is 0 and L istriethoxysilylpropyl or trimethoxysilylpropyl. Such an amidine of theformula (I) is particularly suitable as catalyst for compositionscontaining silane groups, where it can be covalently bonded via thesilane groups in the course of curing.

If Q is an N-aziridinyl group, L is preferably a (p+r)-valenthydrocarbyl radical which has an average molecular weight in the rangefrom 15 to 2,000 g/mol, especially 87 to 500 g/mol, and especially hasoxygen in the form of ester groups.

If Q is a (meth)acrylate or (meth)acrylamide or itaconate or itaconamidegroup, L is preferably a (p+r)-valent hydrocarbyl radical which has anaverage molecular weight in the range from 15 to 5,000 g/mol, especially15 to 2,000 g/mol, and optionally has oxygen or nitrogen or silicon inthe form of ether, tertiary amino, ester, urethane, isocyanurate,biuret, allophanate and/or alkoxysilane groups, especially a radicalselected from the group consisting of butyl, 2-ethylhexyl,trimethoxysilylpropyl, triethoxysilylpropyl, 1,2-ethylene,3,6,9-trioxa-1,11-undecylene, 2,5-dimethyl-3,6-dioxa-1,8-nonylene, apolyoxyethylene radical having a molecular weight in the range from 200to 2,000 g/mol, a polyoxypropylene radical having a molecular weight inthe range from 200 to 2,000 g/mol, 1,4-butylene, 1,6-hexylene,2,2-dimethyl-1,3-propylene, trimethylolpropane after removal of thethree hydroxyl groups, and polyurethane polymers having (meth)acrylategroups and having an average molecular weight in the range from 500 to5,000 g/mol, especially 500 to 2,000 g/mol, especially from the reactionof 2-hydroxyethyl acrylate with polyurethane polymers containingisocyanate groups.

More preferably, p is 1 and r is 0 and L is triethoxysilylpropyl ortrimethoxysilylpropyl. Such an amidine of the formula (I) isparticularly suitable as catalyst for compositions containing silanegroups, where it can be covalently bonded via the silane groups in thecourse of curing.

If Q is a maleate or maleamide or fumarate or fumaramide group, L ispreferably a monovalent hydrocarbyl radical having 1 to 8 carbon atoms,especially methyl or ethyl or butyl.

If Q is a maleimide group, L is preferably a hydrogen radical or a mono-or divalent hydrocarbyl radical having 1 to 12 carbon atoms, especiallya hydrogen radical or methyl, ethyl, butyl or hexyl, or 1,2-ethylene or1,4-butylene or 1,6-hexylene.

The reaction of the amidine of the formula HZ with the functionalcompound of the formula L

Q]_((p+r)) is especially effected under conditions as typically used forreactions between the reactive groups involved in the particularreaction, preferably at a temperature in the range from 20 to 160° C.,especially to 140° C. The reaction can be effected with use of a solventor preferably in a solvent-free manner. It is optionally possible toalso use auxiliaries, for example catalysts, initiators or stabilizers.Preferably, no solvents and auxiliaries are used in the reaction.

The amidine of the formula HZ is preferably used in a roughlystoichiometric or slightly superstoichiometric amount in relation to thereactive groups of the functional compound. This reaction is preferablyconducted such that all the reactive groups of the functional compoundare converted.

The reaction product from this reaction is preferably used, withoutworkup or purification, as catalyst for the crosslinking of a curablecomposition. The reaction product here may contain proportions ofby-products or unconverted starting materials.

The invention thus further provides a process for preparing the amidineof the formula (I), wherein at least one amidine of the formula HZ isreacted with at least one functional compound of the formula L

Q]_((p+r)), as described above.

If the functional compound of the formula L

Q]_((p+r)) has more than one reactive group, these are preferably thesame, as, for example, in diglycidyls or triacrylates. Alternatively, itis possible that the functional compound has various reactive groups.

Suitable functional compounds of the formula L

Q]_((p+r)) are especially commercially available substances.

Preferred functional compounds of the formula L

Q]_((p+r)) are

-   -   glycidyl ethers or glycidyl esters, especially aliphatic        glycidyl ethers, preferably allyl glycidyl ether, butyl glycidyl        ether, hexyl glycidyl ether, 2-ethylhexyl glycidyl ether,        glycidyl ethers of fatty alcohols, such as, in particular, C₈-        to C₁₀-alkyl glycidyl ethers or C₁₂- to C₁₄-alkyl glycidyl        ethers, epoxysilanes such as, in particular,        3-glycidoxypropyltrimethoxysilane,        3-glycidoxypropyltriethoxysilane,        3-glycidoxypropyldimethoxymethylsilane or        3-glycidoxypropyldiethoxymethylsilane, glycidyl ethers of        phenol, cresol, tert-butylphenol or cardanol, or aliphatic        polyglycidyl ethers, preferably glycidyl ethers of ethylene        glycol, propylene glycol, butylene glycol, hexanediol,        octanediol, polypropylene glycols, dimethylolcyclohexane,        neopentyl glycol, castor oil, trimethylolpropane,        trimethylolethane, pentaerythritol, glycerol, alkoxylated        glycerol or alkoxylated trimethylolpropane, or ring-hydrogenated        bisphenol A, F or A/F liquid resins; or aromatic polyglycidyl        ethers, preferably glycidyl ethers of bisphenol A, bisphenol F        or bisphenol A/F, or novolak glycidyl ethers, especially in the        form of what are called liquid resins, as are commercially        available, for example, from Dow, Huntsman or Hexion;    -   N-alkylaziridines, especially Michael adducts of aziridine or        2-methylaziridine, preferably methyl        3-(aziridin-1-yl)propanoate, methyl        3-(2-methylaziridin-1-yl)-propanoate, butyl        3-(aziridin-1-yl)propanoate, butyl        3-(2-methylaziridin-1-yl)-propanoate, 1,1,1-trimethylolpropane        tris(3-(aziridin-1-yl)-propanoate), 1,1,1-trimethylolpropane        tris(3-(2-methylaziridin-1-yl)propanoate), pentaerythritol        tetrakis (3-(aziridin-1-yl)propanoate or pentaerythritol        tetrakis(3-(2-methylaziridin-1-yl)propanoate);    -   (meth)acrylates, especially acrylates or methacrylates,        preferably methyl (meth)acrylate, ethyl (meth)acrylate, butyl        (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl        (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate,        cyclohexyl (meth)acrylate, tetrahydrofuryl (meth)acrylate,        isobornyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate,        2-(2-phenoxyethoxy)ethyl (meth)acrylate, 2-(4-nonylphenoxy)ethyl        (meth)acrylate, 3-(meth)acryloyloxypropyltrimethoxysilane,        3-(meth)acryloyloxypropyltriethoxysilane,        3-(meth)acryloyloxypropyldimethoxymethylsilane or        3-(meth)acryloyloxypropyldiethoxymethylsilane; di- or        polyfunctional acrylates or methacrylates of polyethers,        polyesters, novolaks, phenols, aliphatic or cycloaliphatic        alcohols, glycols, polyester glycols or mono- or polyalkoxylated        derivatives of the aforementioned compounds, preferably ethylene        glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate,        tripropylene glycol di(meth)acrylate, polyethylene glycol        di(meth)acrylate, polypropylene glycol di(meth)acrylate,        butane-1,4-diol di(meth)acrylate, hexane-1,6-diol        di(meth)acrylate, neopentyl glycol di(meth)acrylate,        trimethylolpropane tri(meth)acrylate, pentaerythritol        tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate,        dipentaerythritol penta(meth)acrylate, dipentaerythritol        hexa(meth)acrylate; di- or poly-acryloyl- or        -methacryloyl-functional polybutadienes, polyisoprenes or block        copolymers thereof; adducts of di- or polyfunctional glycidyl        ethers or glycidyl esters, such as those with acrylic acid and        methacrylic acid that have already been mentioned; di- or        polyfunctional polyurethane (meth)acrylates, especially reaction        products of polyurethane polymers containing isocyanate groups        with 2-hydroxyethyl acrylate; or tris(2-hydroxyethyl)        isocyanurate tri(meth)acrylate or tris(2-hydroxyethyl) cyanurate        tri(meth)acrylate;    -   (meth)acrylamides, especially acrylamide, methacrylamide or        N-substituted acrylamides or methacrylamides, preferably        N,N-dimethylacrylamide,        N,N-diethylacrylamide,N-methylacrylamide, N-ethylacrylamide,        N-propylacrylamide, N-isopropylacrylamide, N-butylacrylamide,        N-tert-butylacrylamide, N,N-dimethylaminopropylacrylamide,        N-butoxymethylacrylamide or N-isobutoxymethylacrylamide; or di-        or polyfunctional acrylamides or methacrylamides, preferably        N,N′-methylenebis(acrylamide), N,N′-ethylenebis(acrylamide) or        N,N′,N″-tris((meth)acryloyl)perhydrotriazine, or cyclic        (meth)acrylamides, especially 4-acryloylmorpholine;    -   maleates, especially dialkyl maleates, preferably dimethyl        maleate, diethyl maleate or dibutyl maleate;    -   maleimides, especially maleimide or N-alkylmaleimides,        preferably N-methylmaleimide, N-ethylmaleimide,        N-butylmaleimide, N-hexylmaleimide or        1,1-(1,6-hexylene)bis(1H-pyrrole-2,5-dione);    -   itaconates, especially dialkyl itaconates, preferably dimethyl        itaconate, diethyl itaconate, dibutyl itaconate or dihexyl        itaconate.

More preferably, the functional compound of the formula L

Q]_((p+r)) is selected from the group consisting of 2-ethylhexylglycidyl ether, C₈- to C₁₀-alkyl glycidyl ether, C₁₂- to C₁₄-alkylglycidyl ether, cresyl glycidyl ether, tert-butylphenyl glycidyl ether,cardanol glycidyl ether, butane-1,4-diol diglycidyl ether,hexane-1,6-diol diglycidyl ether, neopentyl glycol diglycidyl ether,polypropylene glycol diglycidyl ether having an average molecular weightin the range from 280 to 1,000 g/mol, bisphenol A diglycidyl ether,bisphenol F diglycidyl ether, 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropyltriethoxysilane, butyl (meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl (meth)acrylate,(meth)acryloyloxypropyltrimethoxysilane,(meth)acryloyloxypropyltriethoxysilane, ethylene glycoldi(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropyleneglycol di(meth)acrylate, polyethylene glycol di(meth)acrylate having anaverage molecular weight in the range from 200 to 2,000 g/mol,polypropylene glycol di(meth)acrylate having an average molecular weightin the range from 200 to 2,000 g/mol, butane-1,4-diol di(meth)acrylate,hexane-1,6-diol di(meth)acrylate, neopentyl glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, di- or polyfunctional polyurethane(meth)acrylates having an average molecular weight in the range from 500to 5,000 g/mol from the reaction of polyurethane polymers containingisocyanate groups with 2-hydroxyethyl acrylate, 4-acryloylmorpholine,acrylonitrile, diethyl maleate, diethyl fumarate, N-ethylmaleimide anddiethyl itaconate.

In a preferred embodiment of the invention, the amidine of the formula(I) is free of hydroxyl groups. More preferably, the functional compoundof the formula L

Q]_((p+r)) is selected from the group consisting of butyl(meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate,(meth)acryloyloxypropyltrimethoxysilane,(meth)acryloyloxypropyltriethoxysilane, ethylene glycoldi(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropyleneglycol di(meth)acrylate, polyethylene glycol di(meth)acrylate having anaverage molecular weight in the range from 200 to 2,000 g/mol,polypropylene glycol di(meth)acrylate having an average molecular weightin the range from 200 to 2,000 g/mol, butane-1,4-diol di(meth)acrylate,hexane-1,6-diol di(meth)acrylate, neopentyl glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, di- or polyfunctional polyurethane(meth)acrylates having an average molecular weight in the range from 500to 5,000 g/mol from the reaction of polyurethane polymers containingisocyanate groups with 2-hydroxyethyl acrylate, 4-acryloylmorpholine,acrylonitrile, diethyl maleate, diethyl fumarate, N-ethylmaleimide anddiethyl itaconate.

In a further preferred embodiment of the invention, the amidine of theformula (I) contains a silane group and especially has the formula (I′)or the formula (I″).

This functional compound of the formula L

Q]_((p+r)) is especially selected from the group consisting of3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane,(meth)acryloyloxypropyltrimethoxysilane and(meth)acryloyloxypropyltriethoxysilane.

The amidine of the formula HZ especially has the formula

where R¹, R² and R³ have the definitions already given.

A preferred amidine of the formula HZ is a cyclic amidine of the formula

Such a cyclic amidine is preparable in a particularly simple manner.

The cyclic amidine of the formula HZ is preferably selected from thegroup consisting of imidazoline, 2-methylimidazoline,4(5)-methylimidazoline, 2,4(5)-dimethylimidazoline,4,4(5,5)-dimethylimidazoline, 2,4,4(2,5,5)-trimethylimidazoline,1,4,5,6-tetrahydropyrimidine, 2-methyl-1,4,5,6-tetrahydropyrimidine,5,5-dimethyl-1,4,5,6-tetrahydropyrimidine,2,5,5-trimethyl-1,4,5,6-tetrahydropyrimidine,4(6)-methyl-1,4,5,6-tetrahydropyrimidine,2,4(2,6)-dimethyl-1,4,5,6-tetrahydropyrimidine,4(6)-ethyl-1,4,5,6-tetrahydropyrimidine and4(6)-ethyl-2-methyl-1,4,5,6-tetrahydropyrimidine. Among these,preference is given to imidazoline, 2-methylimidazoline,1,4,5,6-tetrahydropyrimidine or 2-methyl-1,4,5,6-tetrahydropyrimidine.

Most preferred is 2-methyl-1,4,5,6-tetrahydropyrimidine.

An especially preferred amidine of the formula (I) is one which has beenobtained from the reaction of 2-methyl-1,4,5,6-tetrahydropyrimidine witha functional compound selected from the group consisting of 2-ethylhexylglycidyl ether, C₈- to C₁₀-alkyl glycidyl ether, C₁₂- to C₁₄-alkylglycidyl ether, cresyl glycidyl ether, tert-butylphenyl glycidyl ether,cardanol glycidyl ether, butane-1,4-diol diglycidyl ether,hexane-1,6-diol diglycidyl ether, neopentyl glycol diglycidyl ether,polypropylene glycol diglycidyl ether having an average molecular weightin the range from 280 to 1,000 g/mol, bisphenol A diglycidyl ether,bisphenol F diglycidyl ether, 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropyltriethoxysilane, butyl (meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl (meth)acrylate,(meth)acryloyloxypropyltrimethoxysilane,(meth)acryloyloxypropyltriethoxysilane, ethylene glycoldi(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropyleneglycol di(meth)acrylate, polyethylene glycol di(meth)acrylate having anaverage molecular weight in the range from 200 to 2,000 g/mol,polypropylene glycol di(meth)acrylate having an average molecular weightin the range from 200 to 2,000 g/mol, butane-1,4-diol di(meth)acrylate,hexane-1,6-diol di(meth)acrylate, neopentyl glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, di- or polyfunctional polyurethane(meth)acrylates having an average molecular weight in the range from 500to 5,000 g/mol from the reaction of polyurethane polymers containingisocyanate groups with 2-hydroxyethyl acrylate, 4-acryloylmorpholine,acrylonitrile, diethyl maleate, diethyl fumarate, N-ethylmaleimide anddiethyl itaconate.

A very particularly preferred amidine of the formula (I) is one which isfree of hydroxyl groups and has been obtained from the reaction of2-methyl-1,4,5,6-tetrahydropyrimidine with a functional compoundselected from the group consisting of butyl (meth)acrylate, tert-butyl(meth)acrylate, 2-ethylhexyl (meth)acrylate,(meth)acryloyloxypropyltrimethoxysilane,(meth)acryloyloxypropyltriethoxysilane, ethylene glycoldi(meth)acrylate, tetraethylene glycol di(meth)acrylate, tripropyleneglycol di(meth)acrylate, polyethylene glycol di(meth)acrylate having anaverage molecular weight in the range from 200 to 2,000 g/mol,polypropylene glycol di(meth)acrylate having an average molecular weightin the range from 200 to 2,000 g/mol, butane-1,4-diol di(meth)acrylate,hexane-1,6-diol di(meth)acrylate, neopentyl glycol di(meth)acrylate,trimethylolpropane tri(meth)acrylate, di- or polyfunctional polyurethane(meth)acrylates having an average molecular weight in the range from 500to 5,000 g/mol from the reaction of polyurethane polymers containingisocyanate groups with 2-hydroxyethyl acrylate, 4-acryloylmorpholine,acrylonitrile, diethyl maleate, diethyl fumarate, N-ethylmaleimide anddiethyl itaconate.

Very particular preference is further given to an amidine of the formula(I) which contains a silane group and has the formula (I′) or theformula (I″) and has been obtained from the reaction of2-methyl-1,4,5,6-tetrahydropyrimidine with a functional compoundselected from the group consisting of 3-glycidoxypropyltrimethoxysilane,3-glycidoxypropyltriethoxysilane,(meth)acryloyloxypropyltrimethoxysilane and(meth)acryloyloxypropyltriethoxysilane.

A cyclic amidine of the formula

is for its part especially obtained from the reaction of at least onediamine of the formula NH₂—R⁴—NH₂ with at least one reagent forintroduction of amidine groups.

The reaction product from this reaction can be used without furtherworkup for preparation of an amidine of the formula (I).

A suitable diamine of the formula NH₂—R⁴—NH₂ is especiallyethylenediamine, propane-1,2-diamine, propane-1,3-diamine,2-methylpropane-1,2-diamine, 2,2-dimethylpropane-1,3-diamine,butane-1,3-diamine, butane-1,4-diamine, pentane-1,3-diamine (DAMP),1,2-diaminocyclohexane, 1,3-diaminocyclohexane or2(4)-methyl-1,3-diaminocyclohexane. Preference is given toethylenediamine, propane-1,2-diamine, propane-1,3-diamine,2-methylpropane-1,2-diamine, 2,2-dimethylpropane-1,3-diamine,butane-1,3-diamine or pentane-1,3-diamine (DAMP). Particular preferenceis given to ethylenediamine or propane-1,3-diamine.

Most preferred is propane-1,3-diamine.

The reagent for introduction of amidine groups is preferably selectedfrom the group consisting of ortho esters, 1,3-keto esters, 1,3-ketoamides, nitriles, imido esters, imidoyl chlorides, amide and lactams.

Among these, preference is given to ortho esters, 1,3-keto esters ornitriles. Preferred ortho esters are ortho esters of the formulaR³—C(OR⁶)₃ where R⁶ is an alkyl radical having 1 to 4 carbon atoms andR³ has the definitions already given, especially an orthoformate,orthoacetate, orthopropionate, orthobutyrate or orthovalerate, morepreferably trimethyl orthoformate, triethyl orthoformate, trimethylorthoacetate or triethyl orthoacetate.

Preferred 1,3-keto esters are 1,3-keto esters of the formulaR³—C(O)CH₂C(O)OR⁶ where R⁶ and R³ have the definitions already given,especially methyl acetoacetate, ethyl acetoacetate, isopropylacetoacetate or tert-butyl acetoacetate, more preferably ethylacetoacetate.

Preferred nitriles are nitriles of the formula R³—CN where R³ has thedefinitions already given, especially acetonitrile, propionitrile,butyronitrile, isobutyronitrile, valeronitrile or capronitrile, morepreferably acetonitrile.

The reagent for introduction of amidine groups is more preferablyselected from the group consisting of trimethyl orthoformate, triethylorthoformate, trimethyl orthoacetate, triethyl orthoacetate, methylacetoacetate, ethyl acetoacetate, isopropyl acetoacetate, tert-butylacetoacetate and acetonitrile.

With these reagents, cyclic amidines of the formula HZ are obtained in aparticularly simple manner, which enable amidines of the formula (I)having particularly high catalytic activity.

The reaction is preferably conducted at elevated temperature, optionallyunder elevated pressure and optionally in the presence of a catalyst,wherein elimination products released from the reagent, such asalcohols, esters or amines, are preferably removed during or after thereaction, especially by means of distillation, optionally under reducedpressure.

Preferably, the ratio between the diamine and the reagent is chosen suchthat the reagent is fully converted in the reaction. More preferably,the diamine and the reagent are used in a molar ratio of about 1:1 to1.5:1, especially 1:1 to 1.2:1.

If an ortho ester is used, the reaction is preferably effected at atemperature of 40 to 160° C., especially 60 to 140° C., the alcoholreleased preferably being removed by distillation. A catalyst isoptionally used here, especially an acid.

If a 1,3-keto ester is used, the reaction is preferably effected at atemperature of 20 to 100° C., especially 40 to 80° C., the esterreleased preferably being removed by distillation. A catalyst ispreferably used here, especially an acid, preferably a sulfonic acid.

If a nitrile is used, the reaction is preferably effected at atemperature of 60 to 180° C., especially 80 to 160° C., optionally underelevated pressure, the ammonia released preferably being removed bydistillation. A catalyst is preferably used here, especially a Lewisacid, preferably boron trifluoride etherate, lithium perchlorate, zincchloride, zinc(III) trifluoromethanesulfonate or lanthanum(III)trifluoromethanesulfonate.

In a preferred amidine of the formula (I), p is an integer from 1 to 4,preferably 1 or 2 or 3, especially 1 or 2, r is 0, Q′ is

L is a p-valent hydrocarbyl radical which has an average molecularweight in the range from 15 to 1,500 g/mol and optionally contains etheroxygens and optionally an alkoxysilane group, and Z is a cyclic amidinegroup. Such an amidine especially has the formula (Ia).

In this formula, L is preferably a radical selected from the groupconsisting of 2-ethylhexyl glycidyl ether, C₈- to C₁₀-alkyl glycidylether, C₁₂- to C₁₄-alkyl glycidyl ether, cresyl glycidyl ether,tert-butylphenyl glycidyl ether, cardanol glycidyl ether,butane-1,4-diol diglycidyl ether, hexane-1,6-diol diglycidyl ether,neopentyl glycol diglycidyl ether, polypropylene glycol diglycidyl etherhaving an average molecular weight in the range from 280 to 1,500 g/mol,bisphenol A diglycidyl ether, bisphenol F diglycidyl ether,3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane,in each case after removal of the glycidoxy groups.

More preferably, p is 1 and L is triethoxysilylpropyl ortrimethoxysilylpropyl.

Such an amidine is particularly suitable as catalyst for compositionscontaining silane groups, where it can be covalently bonded via thesilane groups in the course of curing.

In a further preferred amidine of the formula (I), p is an integer from1 to 4, r is 0, Q′is

L is a p-valent hydrocarbyl radical which has an average molecularweight in the range from 15 to 5,000 g/mol, especially 15 to 2,000g/mol, more preferably 87 to 500 g/mol, and especially has oxygen in theform of ester groups, and Z is a cyclic amidine group. Such an amidineespecially has the formula (lb).

In a further preferred amidine of the formula (I), p is an integer from1 to 3, r is 0, Q′ is

L is a p-valent hydrocarbyl radical which has an average molecularweight in the range from 15 to 5,000 g/mol, especially 15 to 2,000g/mol, and optionally has oxygen or nitrogen or silicon in the form ofether, tertiary amino, ester, urethane, isocyanurate, biuret,allophanate and/or alkoxysilane groups, and Z is a cyclic amidine group,where, in the case that p=1, L and R⁵ together may also be an optionallysubstituted alkylene radical which has 2 to 6 carbon atoms andoptionally contains an ether oxygen. Such an amidine especially has theformula (Ic).

Preferably, E² here is a hydrogen radical or methyl radical.

Preferably, L here is either a radical selected from butyl,2-ethylhexyl, trimethoxysilylpropyl, triethoxysilylpropyl, 1,2-ethylene,3,6,9-trioxa-1,11-undecylene, 2,5-dimethyl-3,6-dioxa-1,8-nonylene, apolyoxyethylene radical having a molecular weight in the range from 200to 2,000 g/mol, a polyoxypropylene radical having a molecular weight inthe range from 200 to 2,000 g/mol, 1,4-butylene, 1,6-hexylene,2,2-dimethyl-1,3-propylene, trimethylolpropane after removal of threehydroxyl groups, and polyurethane polymers having (meth)acrylate groupsand having an average molecular weight in the range from 500 to 5,000g/mol, especially from the reaction of 2-hydroxyethyl acrylate withpolyurethane polymers containing isocyanate groups, or L and R⁵ togetherare 3-oxa-1,5-pentylene.

In a further preferred amidine of the formula (I), p is 1, r is 0, Q′ is

L is a monovalent hydrocarbyl radical having 1 to 8 carbon atoms and Zis a cyclic amidine group. Such an amidine especially has the formula(Id).

Preferably, L and E³ here are each the same radical.

The invention further provides for the use of an amidine of the formula(I) as described above as catalyst for the crosslinking of a curablecomposition. In this case, it accelerates the crosslinking or curing ofthe composition.

A suitable curable composition is especially

-   -   an epoxy resin composition, especially a high-temperature-curing        system that crosslinks via dicyandiamide or carboxylic acids or        carboxylic anhydrides, as used, for example, in adhesives,        coatings or casting resins; or    -   a polyurethane composition, especially a two-component system        that crosslinks by reaction of polyols with isocyanates, as        used, for example, for adhesives, coverings, potting compounds,        sealing joints, moldings or slabstock foams, or a one-component        system having blocked isocyanate groups or blocked amino groups,        as used, for example, in powder coatings, coil coatings,        electrocoat materials or liquid paints; or    -   an epoxy resin/polyurethane composition; or    -   a cyanate ester resin composition; or    -   a composition containing silane groups.

Preferably, the curable composition is a polyurethane composition or acomposition containing silane groups. In such a composition, the amidineof the formula (I) enables good storage stability and rapid curing.

A particularly advantageous use is for crosslinking of a compositioncontaining silane groups, especially of a composition based on polymerscontaining silane groups. Compositions based on polymers containingsilane groups cure rapidly even when the catalyst concentration isrelatively low and do not have a tendency to migration-related defectssuch as separation, exudation or substrate soiling.

Particular preference is given to the use of the amidine of the formula(I) as catalyst for the crosslinking of a composition based on polymerscontaining silane groups that are selected from the group consisting ofpolyorganosiloxanes having terminal silane groups and organic polymerscontaining silane groups.

A polyorganosiloxane having terminal silane groups has the advantagethat, in the cured state, it is particularly water- and light-stable andenables particularly flexible properties.

An organic polymer containing silane groups has the advantage of havingparticularly good adhesion properties on a multitude of substrates andbeing particularly inexpensive.

The invention thus further provides a curable composition comprising atleast one amidine of the formula (I).

Preferably, the curable composition is an adhesive or a sealant or acoating.

Preferably, the curable composition further comprises at least onepolymer containing silane groups.

A composition of this kind typically has good storability with nopropensity to separation, and because of the low toxicity and lowvolatility of the amidine of the formula (I) allows a low hazardclassification and enables low-emissions and low-odor products that curerapidly and at the same time form a mechanically high-quality anddurable material. A particularly advantageous circumstance here is thatthis material shows barely any propensity to migration-related defectssuch as exudation or substrate soiling, by contrast with compositionscomprising catalysts according to the prior art, for example DBU or TMG.Compositions comprising such catalysts known from the prior art have apropensity to migration effects, which can be manifested prior to curingby separation and after curing by tacky and/or greasy surfaces and/orsubstrate soiling. Particularly the latter effects are extremelyundesirable, since tacky and greasy surfaces are rapidly soiled and aredifficult to paint over, and substrate contaminants can lead to lastingdiscoloration.

In a preferred embodiment, the polymer containing silane groups is apolyorganosiloxane having terminal silane groups.

A preferred polyorganosiloxane having terminal silane groups has theformula (IV)

where

R, R′ and R″ are each independently a monovalent hydrocarbyl radicalhaving 1 to 12 carbon atoms;

G is a hydroxyl radical or an alkoxy, acetoxy, ketoximato, amido orenoxy radical having 1 to 13 carbon atoms;

a is 0, 1 or 2; and

m is an integer in the range from 50 to about 2,500.

R is preferably methyl, vinyl or phenyl.

R′ and R″ are preferably each independently an alkyl radical having 1 to5, preferably 1 to 3, carbon atoms, especially methyl.

G is preferably a hydroxyl radical or an alkoxy or ketoximato radicalhaving 1 to 6 carbon atoms, especially a hydroxyl, methoxy, ethoxy,methylethylketoximato or methylisobutylketoximato radical.

More preferably, G is a hydroxyl radical.

a is preferably 0 or 1, especially 0.

In addition, m is preferably chosen such that the polyorganosiloxane ofthe formula (IV) has a viscosity at room temperature in the range from100 to 500,000 mPa·s, especially from 1000 to 100,000 mPa·s.

Polyorganosiloxanes of the formula (IV) are easy to handle and crosslinkwith moisture and/or silane crosslinkers to give solid silicone polymershaving elastic properties.

Suitable commercially available polyorganosiloxanes of the formula (IV)are available, for example, from Wacker, Momentive Performance Material,GE Advanced Materials, Dow Corning, Bayer or Shin Etsu.

Preferably, the composition comprises, in addition to thepolyorganosiloxane having terminal silane groups, a silane crosslinker,especially a silane of the formula (V),(R′″)_(q)—Si—(G′)_(4-q)  (V)

where

R′″ is a monovalent hydrocarbyl radical having 1 to 12 carbon atoms,

G′ is a hydroxyl radical or is an alkoxy, acetoxy, ketoximato, amido orenoxy radical having 1 to 13 carbon atoms; and

q has a value of 0, 1 or 2, especially 0 or 1.

Particularly suitable silanes of the formula (V) aremethyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane,vinyltrimethoxysilane, methyltriethoxysilane, vinyltriethoxysilane,phenyltriethoxysilane, tetramethoxysilane, tetraethoxysilane,methyltris(methylethylketoximo)silane,vinyltris(methylethylketoximo)silane andmethyltris(isobutylketoximo)silane.

In a further preferred embodiment, the polymer containing silane groupsis an organic polymer containing silane groups, especially a polyolefin,polyester, polyamide, poly(meth)acrylate or polyether or a mixed form ofthese polymers, each of which bears one or preferably more than onesilane group. The silane groups may be in pendant positions in the chainor in terminal positions and are bonded to the organic polymer via acarbon atom.

More preferably, the organic polymer containing silane groups is apolyolefin containing silane groups or a polyester containing silanegroups or a poly(meth)acrylate containing silane groups or a polyethercontaining silane groups or a mixed form of these polymers.

Most preferably, the organic polymer containing silane groups is apolyether containing silane groups.

The silane groups present in the organic polymer containing silanegroups are preferably alkoxysilane groups, especially alkoxysilanegroups of the formula (VI)

where

R¹⁴ is a linear or branched, monovalent hydrocarbyl radical having 1 to5 carbon atoms, especially methyl or ethyl or isopropyl;

R¹⁵ is a linear or branched, monovalent hydrocarbyl radical having 1 to8 carbon atoms, especially methyl or ethyl; and

x is a value of 0 or 1 or 2, preferably 0 or 1, especially 0.

More preferably R¹⁴ is methyl or ethyl.

Particular preference is given to trimethoxysilane groups,dimethoxymethylsilane groups or triethoxysilane groups.

In this context, methoxysilane groups have the advantage that they areparticularly reactive, and ethoxysilane groups have the advantage thatthey are toxicologically advantageous and particularly storage-stable.

The organic polymer containing silane groups has an average ofpreferably 1.3 to 4, especially 1.5 to 3, more preferably 1.7 to 2.8,silane groups per molecule.

The silane groups are preferably terminal.

The organic polymer containing silane groups preferably has an averagemolecular weight in the range from 1,000 to 30,000 g/mol, especiallyfrom 2,000 to 20,000 g/mol. The organic polymer containing silane groupspreferably has a silane equivalent weight of 300 to 25,000 g/eq,especially of 500 to 15,000 g/eq.

The organic polymer containing silane groups may be solid or liquid atroom temperature. It is preferably liquid at room temperature.

Most preferably, the organic polymer containing silane groups is apolyether containing silane groups which is liquid at room temperature,where the silane groups are especially dialkoxysilane groups and/ortrialkoxysilane groups, more preferably trimethoxysilane groups ortriethoxysilane groups.

Processes for preparing polyethers containing silane groups are known tothe person skilled in the art.

In a preferred process, polyethers containing silane groups areobtainable from the reaction of polyethers containing allyl groups withhydrosilanes, optionally with chain extension using, for example,diisocyanates.

In a further preferred process, polyethers containing silane groups areobtainable from the copolymerization of alkylene oxides andepoxysilanes, optionally with chain extension using, for example,diisocyanates.

In a further preferred process, polyethers containing silane groups areobtainable from the reaction of polyether polyols withisocyanatosilanes, optionally with chain extension using diisocyanates.

In a further preferred process, polyethers containing silane groups areobtainable from the reaction of polyethers containing isocyanate groups,especially NCO-terminated urethane polyethers from the reaction ofpolyether polyols with a superstoichiometric amount of polyisocyanates,with aminosilanes, hydroxysilanes or mercaptosilanes. Polyetherscontaining silane groups from this process are particularly preferred.This process enables the use of a multitude of inexpensive startingmaterials of good commercial availability, by means of which it ispossible to obtain different polymer properties, for example highextensibility, high strength, low modulus of elasticity, low glasstransition point or high weathering resistance.

More preferably, the polyether containing silane groups is obtainablefrom the reaction of NCO-terminated urethane polyethers withaminosilanes or hydroxysilanes. Suitable NCO-terminated urethanepolyethers are obtainable from the reaction of polyether polyols,especially polyoxyalkylenediols or polyoxyalkylenetriols, preferablypolyoxypropylenediols or polyoxypropylenetriols, with asuperstoichiometric amount of polyisocyanates, especially diisocyanates.

Preferably, the reaction between the polyisocyanate and the polyetherpolyol is conducted with exclusion of moisture at a temperature of 50°C. to 160° C., optionally in the presence of suitable catalysts, withmetered addition of the polyisocyanate in such a way that the isocyanategroups thereof are present in a stoichiometric excess in relation to thehydroxyl groups of the polyol. More particularly, the excess ofpolyisocyanate is chosen such that a content of free isocyanate groupsof 0.1% to 5% by weight, preferably 0.2% to 4% by weight, morepreferably 0.3% to 3% by weight, based on the overall polymer, remainsin the resulting urethane polyether after the reaction of all hydroxylgroups. Preferred diisocyanates are selected from the group consistingof hexamethylene 1,6-diisocyanate (HDI),1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate or IPDI), tolylene 2,4- and 2,6-diisocyanate and anydesired mixtures of these isomers (TDI) and diphenylmethane 4,4′-, 2,4′-and 2,2′-diisocyanate and any desired mixtures of these isomers (MDI).Particular preference is given to IPDI or TDI. Most preferred is IPDI.In this way, polyethers containing silane groups with particularly goodlightfastness are obtained.

Especially suitable as polyether polyols are polyoxyalkylenediols orpolyoxyalkylenetriols having a degree of unsaturation lower than 0.02meq/g, especially lower than 0.01 meq/g, and an average molecular weightin the range from 400 to 25,000 g/mol, especially 1000 to 20,000 g/mol.

As well as polyether polyols, it is also possible to use portions ofother polyols, especially polyacrylate polyols, and low molecular weightdiols or triols.

Suitable aminosilanes for the reaction with an NCO-terminated urethanepolyether are primary and secondary aminosilanes. Preference is given to3-aminopropyltrimethoxysilane, 3-aminopropyldimethoxymethylsilane,4-aminobutyltrimethoxysilane, 4-amino-3-methylbutyltrimethoxysilane,4-amino-3,3-dimethylbutyltrimethoxysilane,N-butyl-3-aminopropyltrimethoxysilane,N-phenyl-3-aminopropyltrimethoxysilane, adducts formed from primaryaminosilanes such as 3-aminopropyltrimethoxysilane,3-aminopropyldimethoxymethylsilane orN-(2-aminoethyl)-3-aminopropyltrimethoxysilane and Michael acceptorssuch as acrylonitrile, (meth)acrylic esters, (meth)acrylamides, maleicor fumaric diesters, citraconic diesters or itaconic diesters,especially dimethyl or diethylN-(3-trimethoxysilylpropyl)aminosuccinate. Likewise suitable are analogsof the aminosilanes mentioned with ethoxy or isopropoxy groups in placeof the methoxy groups on the silicon.

Suitable hydroxysilanes for the reaction with an NCO-terminated urethanepolyether are especially obtainable from the addition of aminosilanesonto lactones or onto cyclic carbonates or onto lactides.

Aminosilanes suitable for this purpose are especially3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,4-aminobutyltrimethoxysilane, 4-aminobutyltriethoxysilane,4-amino-3-methylbutyltrimethoxysilane,4-amino-3-methylbutyltriethoxysilane,4-amino-3,3-dimethylbutyltrimethoxysilane,4-amino-3,3-dimethylbutyltriethoxysilane, 2-aminoethyltrimethoxysilaneor 2-aminoethyltriethoxysilane. Particular preference is given to3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane,4-amino-3,3-dimethylbutyltrimethoxysilane or4-amino-3,3-dimethylbutyltriethoxysilane.

Suitable lactones are especially γ-valerolactone, γ-octalactone,δ-decalactone, and ε-decalactone, especially γ-valerolactone.

Suitable cyclic carbonates are especially4,5-dimethyl-1,3-dioxolan-2-one, 4,4-dimethyl-1,3-dioxolan-2-one,4-ethyl-1,3-dioxolan-2-one, 4-methyl-1,3-dioxolan-2-one or4-(phenoxymethyl)-1,3-dioxolan-2-one.

Suitable lactides are especially 1,4-dioxane-2,5-dione (lactide formedfrom 2-hydroxyacetic acid, also called “glycolide”),3,6-dimethyl-1,4-dioxane-2,5-dione (lactide formed from lactic acid,also called “lactide”) and 3,6-diphenyl-1,4-dioxane-2,5-dione (lactideformed from mandelic acid).

Preferred hydroxysilanes which are obtained in this way areN-(3-triethoxysilylpropyl)-2-hydroxypropanamide,N-(3-trimethoxysilylpropyl)-2-hydroxypropanamide,N-(3-triethoxysilylpropyl)-4-hydroxypentanamide,N-(3-triethoxysilylpropyl)-4-hydroxyoctanamide,N-(3-triethoxysilylpropyl)-5-hydroxydecanamide andN-(3-triethoxysilylpropyl)-2-hydroxypropyl carbamate.

In addition, suitable hydroxysilanes are also obtainable from theaddition of aminosilanes onto epoxides or from the addition of aminesonto epoxysilanes.

Preferred hydroxysilanes which are obtained in this way are2-morpholino-4(5)-(2-trimethoxysilylethyl)cyclohexan-1-ol,2-morpholino-4(5)-(2-triethoxysilyl-ethyl)cyclohexan-1-ol or1-morpholino-3-(3-(triethoxysilyl)propoxy)propan-2-ol.

Further suitable polyethers containing silane groups are commerciallyavailable products, especially the following: MS Polymer™ (from KanekaCorp.; especially the S203H, S303H, S227, S810, MA903 and S943products); MS Polymer™ or Silyl™ (from Kaneka Corp.; especially theSAT010, SAT030, SAT200, SAX350, SAX400, SAX725, MAX450, MAX951products); Excestar® (from Asahi Glass Co. Ltd.; especially the S2410,S2420, S3430, S3630 products); SPUR+* (from Momentive PerformanceMaterials; especially the 1010LM, 1015LM, 1050MM products); Vorasil™(from Dow Chemical Co.; especially the 602 and 604 products); Desmoseal®(from Bayer MaterialScience AG; especially the S XP 2458, S XP 2636, SXP 2749, S XP 2774 and S XP 2821 products), TEGOPAC® (from EvonikIndustries AG; especially the Seal 100, Bond 150, Bond 250 products),Polymer ST (from Hanse Chemie AG/Evonik Industries AG, especially the47, 48, 61, 61 LV, 77, 80, 81 products); Geniosil® STP (from WackerChemie AG; especially the E10, E15, E30, E35 products).

Particularly preferred organic polymers containing silane groups haveend groups of the formula (VII)

where

R¹⁶ is a linear or branched divalent hydrocarbyl radical which has 1 to12 carbon atoms and optionally has cyclic and/or aromatic moieties andoptionally one or more heteroatoms, especially one or more nitrogenatoms;

T is a divalent radical selected from —O—, —S—, —N(R¹⁷)—, —O—CO—N(R¹⁷)—,—N(R¹⁷)—CO—O— and —N(R¹⁷)—CO—N(R¹⁷)—,

-   -   where R¹⁷ is a hydrogen radical or a linear or branched        hydrocarbyl radical which has 1 to 20 carbon atoms and        optionally has cyclic moieties, and which optionally has an        alkoxysilane, ether or carboxylic ester group; and

R¹⁴, R¹⁵ and x have the definitions already given.

Preferably, R¹⁶ is 1,3-propylene or 1,4-butylene, where butylene may besubstituted by one or two methyl groups.

More preferably, R¹⁶ is 1,3-propylene.

Preferably, the amidine of the formula (I) is present in the curablecomposition in such an amount that the concentration of amidine groupsbased on the amount of the crosslinkable polymer is in the range from0.1 to 50 mmol/100 g of polymer, preferably 0.2 to 50 mmol/100 g ofpolymer, especially 0.5 to 20 mmol/100 g.

Such a composition has good storability and rapid curing.

In addition to the amidine of the formula (I), the composition maycomprise further catalysts, especially for the crosslinking of silanegroups. Suitable further catalysts are especially metal compounds and/orbasic nitrogen or phosphorus compounds.

Suitable metal compounds are especially compounds of tin, titanium,zirconium, aluminum or zinc, especially diorganotin(IV) compounds suchas, in particular, dibutyltin(IV) diacetate, dibutyltin(IV) dilaurate,dibutyltin(IV) dineodecanoate or dibutyltin(IV) bis(acetylacetonate) anddioctyltin(IV) dilaurate, and also titanium(IV) or zirconium(IV) oraluminum(III) or zinc(II) complexes, especially with alkoxy,carboxylate, 1,3-diketonate, 1,3-ketoesterate or 1,3-ketoamidateligands.

Suitable basic nitrogen or phosphorus compounds are especiallyimidazoles, pyridines, phosphazene bases or preferably amines,hexahydrotriazines, biguanides, guanidines or further amidines.

Suitable amines are, in particular, alkyl-, cycloalkyl- or aralkylaminessuch as triethylamine, triisopropylamine, 1-butylamine, 2-butylamine,tert-butylamine, 3-methyl-1-butylamine, 3-methyl-2-butylamine,dibutylamine, tributylamine, hexylamine, dihexylamine, cyclohexylamine,dicyclohexylamine, dimethylcyclohexylamine, benzylamine, dibenzylamine,dimethylbenzylamine, octylamine, 2-ethylhexylamine,di-(2-ethylhexyl)amine, laurylamine, N,N-dimethyllaurylamine,stearylamine, N,N-dimethylstearylamine; fatty amines derived fromnatural fatty acid mixtures, such as, in particular, cocoalkylamine, N,N-dimethylcocoalkylamine, C₁₆₋₂₂-alkylamine, N,N-dimethyl-C₁₆₋₂₂-alkylamine, soyaalkylamine,N,N-dimethylsoyaalkylamine, oleylamine, N,N-dimethyloleylamine,tallowalkylamine or N,N-dimethyltallowalkylamine, obtainable for exampleunder the trade names Armeen® (from Akzo Nobel) or Rofamin® (fromEcogreen Oleochemicals); aliphatic, cycloaliphatic or araliphaticdiamines such as ethylenediamine, butanediamine, hexamethylenediamine,dodecanediamine, neopentanediamine, 2-methylpentamethylenediamine(MPMD), 2,2(4),4-trimethylhexamethylenediamine (TMD), isophoronediamine(IPD), 2,5(2,6)-bis(aminomethyl)bicyclo[2.2.1]heptane (NBDA),xylylene-1,3-diamine (MXDA), N,N′-di(tert-butyl)ethylenediamine,N,N,N′,N′-tetramethylethylenediamine,N,N,N′,N′-tetramethylpropylenediamine,N,N,N′,N′-tetramethylhexamethylenediamine, 3-dimethylaminopropylamine,3-(methylamino)propylamine, 3-(cyclohexylamino)propylamine, piperazine,N-methylpiperazine, N,N′-dimethylpiperazine,1,4-diazabicyclo[2.2.2]octane, fatty polyamines such asN-cocoalkylpropane-1,3-diamine, N-oleylpropane-1,3-diamine,N-soyaalkylpropane-1,3-diamine, N-tallowalkylpropane-1,3-diamine orN—(C₁₆₋₂₂-alkyl)propane-1,3-diamine, obtainable for example under thetrade name Duomeen® (from Akzo Nobel); polyalkyleneamines such asdiethylenetriamine, dipropylenetriamine, triethylenetetramine (TETA),tetraethylenepentamine (TEPA), pentamethylenehexamine (PEHA),3-(2-aminoethyl)aminopropylamine,N,N′-bis(3-aminopropyl)ethylenediamine,N-(3-aminopropyl)-N-methylpropanediamine,bis(3-dimethylaminopropyl)amine,N-(3-dimethylaminopropyl)propylene-1,3-diamine,N-(2-aminoethyl)piperazine (N-AEP), N-(2-aminopropyl)piperazine,N,N′-di-(2-amino-ethyl)piperazine,1-methyl-4-(2-dimethylaminoethyl)piperazine,N,N,N′,N″,N″-pentamethyldiethylenetriamine,N,N,N′,N″,N″-pentamethyldipropylenetriamine, polyethyleneiminesobtainable for example under the trade names Lupasol® (from BASF) andEpomin® (from Nippon Shokubai); ether amines, such as, in particular,2-methoxyethylamine, 2-ethoxyethylamine, 3-methoxypropylamine,3-ethoxypropylamine, 3-(2-ethylhexyloxy)propylamine,3-(2-methoxyethoxy)propylamine, 2(4)-methoxyphenylethylamine,morpholine, N-methylmorpholine, N-ethylmorpholine,2-aminoethylmorpholine, bis(2-aminoethyl) ether, bis(dimethylaminoethyl)ether, bis(dimorpholinoethyl) ether, N, N,N′-trimethyl-N′-hydroxyethylbis(2-aminoethyl) ether,3,6-dioxaoctane-1,8-diamine, 4,7-dioxadecane-1,10-diamine,4,7-dioxadecane-2,9-diamine, 4,9-dioxadodecane-1,12-diamine,5,8-dioxadodecane-3,10-diamine, 4,7,10-trioxatridecane-1,13-diamine, or2-aminopropyl-terminated glycols, of the kind obtainable for exampleunder the trade name Jeffamine® (from Huntsman); amino alcohols, suchas, in particular, ethanolamine, isopropanolamine, diethanolamine,diisopropanolamine, triethanolamine, triisopropanolamine,N-butylethanolamine, diglycolamine, N,N-diethylethanolamine,N-methyldiethanolamine, N-methyldiisopropylamine,N,N,N′-trimethylaminoethylethanolamine,N-(3-dimethylaminopropyl)-N,N-diisopropanolamine,N,N-bis(3-dimethylaminopropyl)-N-isopropanolamine,2-(2-dimethylaminoethoxy)ethanolamine, or adducts of mono- andpolyamines with epoxides or diepoxides; amines containing phenol groups,such as, in particular, condensation products of phenols, aldehydes, andamines (so-called Mannich bases and phenalkamines) such as, inparticular, 2-(dimethylaminomethyl)phenol,2,4,6-tris(dimethylaminomethyl)phenol, or polymers of phenol,formaldehyde, and N,N-dimethylpropane-1,3-diamine, and alsophenalkamines obtainable commercially under the brand names Cardolite®(from Cardolite), Aradur® (from Huntsman), and Beckopox® (from Cytec);polyamines containing amide groups, so-called polyamidoamines, of thekind available commercially, for example, under the brand namesVersamid® (from Cognis), Aradur® (from Huntsman), Euretek® (fromHuntsman) or Beckopox® (from Cytec); or aminosilanes, such as, inparticular, 3-aminopropyltrimethoxysilane,3-aminopropyldimethoxymethylsilane,N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,N-(2-aminoethyl)-3-aminopropyl-methyldimethoxysilane,N-(2-aminoethyl)-N′-[3-(trimethoxysilyl)propyl]ethylenediamine or theiranalogs with ethoxy rather than the methoxy groups on the silicon.

Suitable hexahydrotriazines are especially 1,3,5-hexahydrotriazine or1,3,5-tris(3-(dimethylamino)propyl)hexahydrotriazine.

Suitable biguanides are especially biguanide, 1-butylbiguanide,1,1-dimethylbiguanide, 1-butylbiguanide, 1-phenylbiguanide or1-(o-tolyl)biguanide (OTBG).

Suitable guanidines are especially 1-butylguanidine,1,1-dimethylguanidine, 1,3-dimethylguanidine,1,1,3,3-tetramethylguanidine (TMG),2-(3-(trimethoxysilyl)propyl)-1,1,3,3-tetramethylguanidine,2-(3-(methyldimethoxysilyl)propyl)-1,1,3,3-tetramethylguanidine,2-(3-(triethoxysilyl)propyl)-1,1,3,3-tetramethylguanidine,1,5,7-triazabicyclo-[4.4.0]dec-5-ene (TBD),7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene,7-cyclohexyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, 1-phenylguanidine,1-(o-tolyl)guanidine (OTG), 1,3-diphenylguanidine,1,3-di(o-tolyl)guanidine or 2-guanidinobenzimidazole.

Suitable further amidines are especially1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),1,5-diazabicyclo[4.3.0]non-5-ene (DBN),6-dibutylamino-1,8-diazabicyclo[5.4.0]undec-7-ene,6-dibutylamino-1,8-diazabicyclo[5.4.0]undec-7-ene,N,N′-di-n-hexylacetamidine (DHA), 2-methyl-1,4,5,6-tetrahydropyrimidine,1,2-dimethyl-1,4,5,6-tetrahydropyrimidine,2,5,5-trimethyl-1,4,5,6-tetrahydropyrimidine,N-(3-trimethoxysilylpropyl)-4,5-dihydroimidazole orN-(3-triethoxy-silylpropyl)-4,5-dihydroimidazole.

In addition, the composition may comprise, as cocatalyst, an acid,especially a carboxylic acid. Preference is given to aliphaticcarboxylic acids such as formic acid, lauric acid, stearic acid,isostearic acid, oleic acid, 2-ethyl-2,5-dimethylcaproic acid,2-ethylhexanoic acid, neodecanoic acid, fatty acid mixtures from thehydrolysis of natural fats and oils or di- and polycarboxylic acids,especially poly(meth)acrylic acids.

In a preferred embodiment, the composition is essentially free oforganotin compounds. Organotin-free compositions are advantageous interms of protection of health and protection of the environment. Moreparticularly, the tin content of the curable composition is less than0.1% by weight, especially less than 0.05% by weight.

In a further preferred embodiment, the composition comprises acombination of at least one amidine of the formula (I) and at least oneorganotin compound, especially a diorganotin(IV) compound such as thosementioned above. Such a composition has a high curing rate even in thecase of a low tin content, which is advantageous for toxicological andenvironmental reasons.

In one embodiment, the composition additionally comprises, as well asthe amidine of the formula (I), at least one organotitanate. Acombination of an amidine of the formula (I) and an organotitanate hasparticularly high catalytic activity. This enables rapid curing with acomparatively small use amount of organotitanate.

Suitable organotitanates are especially titanium(IV) complexes.

Preferred organotitanates are especially selected from

-   -   titanium(IV) complexes having two 1,3-diketonate ligands,        especially 2,4-pentanedionate (=acetylacetonate), and two        alkoxide ligands;    -   titanium(IV) complexes having two 1,3-ketoesterate ligands,        especially ethylacetoacetate, and two alkoxide ligands;    -   titanium(IV) complexes having one or more aminoalkoxide ligands,        especially triethanolamine or 2-((2-aminoethyl)amino)ethanol,        and one or more alkoxide ligands;    -   titanium(IV) complexes having four alkoxide ligands;    -   and more highly condensed organotitanates, especially oligomeric        titanium(IV) tetrabutoxide, also referred to as polybutyl        titanate;

where suitable alkoxide ligands are especially isobutoxy, n-butoxy,isopropoxy, ethoxy and 2-ethylhexoxy.

Especially suitable are the commercially available products Tyzor® AA,GBA, GBO, AA-75, AA-65, AA-105, DC, BEAT, BTP, TE, TnBT, K™, TOT, TPT orIBAY (all from Dorf Ketal); Tytan PBT, TET, X85, TAA, ET, S2, S4 or S6(all from Borica Company Ltd.) and Ken-React® KR® TTS, 7, 9QS, 12, 26S,33DS, 38S, 39DS, 44, 134S, 138S, 133DS, 158FS or LICA® 44 (all fromKenrich Petrochemicals).

Very particularly suitable organotitanates are selected frombis(ethylaceto-acetato)diisobutoxytitanium(IV) (commercially available,for example, as Tyzor® IBAY from Dorf Ketal),bis(ethylacetoacetato)diisopropoxytitanium(IV) (commercially available,for example, as Tyzor® DC from Dorf Ketal),bis(acetylacetonato)diisopropoxytitanium(IV),bis(acetylacetonato)diisobutoxy-titanium(IV),tris(oxyethyl)amine-isopropoxy-titanium(IV),bis[tris(oxyethyl)-amine]diisopropoxytitanium(IV),bis(2-ethylhexane-1,3-dioxy)titanium(IV),tris[2-((2-aminoethyl)amino)ethoxy]ethoxytitanium(IV),bis(neopentyl(diallyl)oxy)-diethoxytitanium(IV), titanium(IV)tetrabutoxide, tetra(2-ethylhexyloxy) titanate, tetra(isopropoxy)titanate and polybutyl titanate.

Most preferred are bis(ethylacetoacetato)diisobutoxytitanium(IV) orbis(ethylacetoacetato)diisopropoxytitanium(IV).

The composition may comprise further constituents, especially thefollowing auxiliaries and additives:

-   -   adhesion promoters and/or crosslinkers, especially aminosilanes        such as, in particular, 3-aminopropyltrimethoxysilane,        3-aminopropyldimethoxymethylsilane,        N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,        N-(2-aminoethyl)-3-aminopropyldimethoxymethylsilane,        N-(2-aminoethyl)-N′-[3-(trimethoxysilyl)-propyl]ethylenediamine        or the analogs thereof with ethoxy in place of methoxy groups,        and also N-phenyl-, N-cyclohexyl- or N-alkylaminosilanes,        mercaptosilanes, epoxysilanes, (meth)acryloylsilanes,        anhydridosilanes, carbamatosilanes, alkylsilanes or        iminosilanes, oligomeric forms of these silanes, adducts formed        from primary aminosilanes with epoxysilanes or        (meth)acryloylsilanes or anhydridosilanes, amino-functional        alkylsilsesquioxanes, especially amino-functional        methylsilsesquioxane or amino-functional propylsilsesquioxane.        Especially suitable are 3-aminopropyltrimethoxysilane,        3-aminopropyltriethoxysilane,        N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,        N-(2-aminoethyl)-3-aminopropyltriethoxysilane,        3-glycidoxypropyltrimethoxysilane,        3-glycidoxypropyltriethoxysilane or        3-ureidopropyltrimethoxysilane, or oligomeric forms of these        silanes;    -   desiccants, especially tetraethoxysilane, vinyltrimethoxysilane,        vinyltriethoxysilane or organoalkoxysilanes having a functional        group in the α position to the silane group, especially        N-(methyldimethoxysilylmethyl)-O-methylcarbamate,        (methacryloyloxymethyl)silanes, methoxymethylsilanes,        orthoformic esters, calcium oxide or molecular sieves,        especially vinyltrimethoxysilane or vinyltriethoxysilane;    -   plasticizers, especially trialkylsilyl-terminated        polydialkylsiloxanes, preferably trimethylsilyl-terminated        polydimethylsiloxanes, especially having viscosities in the        range from 10 to 1,000 mPa·s, or corresponding compounds in        which some of the methyl groups have been replaced by other        organic groups, especially phenyl, vinyl or trifluoropropyl        groups, called reactive plasticizers, in the form of        monofunctional polysiloxanes, i.e. those that are reactive at        one end, carboxylic esters such as phthalates, especially        dioctyl phthalate, bis(2-ethylhexyl) phthalate,        bis(3-propylheptyl) phthalate, diisononyl phthalate or        diisodecyl phthalate, diesters of ortho-cyclohexane-dicarboxylic        acid, especially diisononyl 1,2-cyclohexanedicarboxylate,        adipates, especially dioctyl adipate, bis(2-ethylhexyl) adipate,        azelates, especially bis(2-ethylhexyl) azelate, sebacates,        especially bis(2-ethylhexyl) sebacate or diisononyl sebacate,        polyols, especially polyoxyalkylene polyols or polyester        polyols, glycol ethers, glycol esters, organic phosphoric or        sulfonic esters, sulfonamides, polybutenes, or fatty acid methyl        or ethyl esters derived from natural fats or oils, also called        “biodiesel”, plasticizers containing siloxane groups being        particularly suitable for polymers containing silane groups in        the form of polyorganosiloxanes;    -   solvents;    -   inorganic or organic fillers, especially natural, ground or        precipitated calcium carbonates, optionally coated with fatty        acids, especially stearic acid, baryte (heavy spar), talcs,        quartz flours, quartz sand, dolomites, wollastonites, kaolins,        calcined kaolins, mica (potassium aluminum silicate), molecular        sieves, aluminum oxides, aluminum hydroxides, magnesium        hydroxide, silicas including finely divided silicas from        pyrolysis processes, industrially produced carbon blacks,        graphite, metal powders such as aluminum, copper, iron, silver        or steel, PVC powder or hollow spheres;    -   fibers, especially glass fibers, carbon fibers, metal fibers,        ceramic fibers or polymer fibers such as polyamide fibers or        polyethylene fibers;    -   dyes;    -   pigments, especially titanium dioxide or iron oxides;    -   rheology modifiers, especially thickeners, especially sheet        silicates such as bentonites, derivatives of castor oil,        hydrogenated castor oil, polyamides, polyurethanes, urea        compounds, fumed silicas, cellulose ethers or hydrophobically        modified polyoxyethylenes;    -   stabilizers against oxidation, heat, light or UV radiation;    -   natural resins, fats or oils such as rosin, shellac, linseed        oil, castor oil or soya oil;    -   non-reactive polymers such as, in particular, homo- or        copolymers of unsaturated monomers, especially from the group        comprising ethylene, propylene, butylene, isobutylene, isoprene,        vinyl acetate or alkyl (meth)acrylates, especially polyethylenes        (PE), polypropylenes (PP), polyisobutylenes, ethylene-vinyl        acetate copolymers (EVA) or atactic poly-α-olefins (APAO);    -   flame-retardant substances, especially the already mentioned        fillers aluminum hydroxide and magnesium hydroxide, or, in        particular, organic phosphoric esters such as, in particular,        triethyl phosphate, tricresyl phosphate, triphenyl phosphate,        diphenyl cresyl phosphate, isodecyl diphenyl phosphate,        tris(1,3-dichloro-2-propyl) phosphate, tris(2-chloroethyl)        phosphate, tris(2-ethylhexyl) phosphate, tris(chloroisopropyl)        phosphate, tris(chloropropyl) phosphate, isopropylated triphenyl        phosphate, mono-, bis- or tris(isopropylphenyl) phosphates of        different degrees of isopropylation, resorcinol bis(diphenyl        phosphate), bisphenol A bis(diphenyl phosphate) or ammonium        polyphosphates;    -   surface-active substances, especially wetting agents, leveling        agents, deaerating agents or defoamers;    -   biocides, especially algicides, fungicides or substances that        inhibit fungal growth;        and other substances customarily used in curable compositions.        It may be advisable to chemically or physically dry certain        constituents before mixing them into the composition.

In a preferred embodiment, the composition comprises at least onedesiccant and at least one adhesion promoter and/or crosslinker.

In a preferred embodiment, the composition does not comprise anyphthalates as plasticizers. Such compositions are toxicologicallyadvantageous and have fewer problems with migration effects.

The composition is preferably produced and stored with exclusion ofmoisture.

Typically, it is storage-stable with exclusion of moisture in a suitablepackage or arrangement, such as, more particularly, a bottle, acanister, a pouch, a bucket, a vat or a cartridge.

The composition may take the form of a one-component or of amulti-component, especially two-component, composition.

In the present document, “one-component” refers to a composition inwhich all constituents of the composition are stored in a mixture in thesame container and which is curable with moisture.

In the present document, “two-component” refers to a composition inwhich the constituents of the composition are present in two differentcomponents which are stored in separate containers. Only shortly beforeor during the application of the composition are the two componentsmixed with one another, whereupon the mixed composition cures,optionally under the action of moisture.

If the composition comprises a polyorganosiloxane having terminal silanegroups, preference is given either to a one-component composition, alsoreferred to as RTV-1, or to a two-component composition, also referredto as RTV-2. In the case of an RTV-2 composition, the polyorganosiloxanehaving terminal silane groups is preferably a constituent of the firstcomponent, and a silane crosslinker, especially a silane crosslinker ofthe formula (VI), is preferably a constituent of the second component.The amidine of the formula (I) may be present in the first and/or thesecond component.

If the composition comprises an organic polymer containing silanegroups, the composition is preferably a one-component composition.

Any second or optionally further components is/are mixed with the firstcomponent prior to or on application, especially by means of a staticmixer or by means of a dynamic mixer.

The composition is especially applied at ambient temperature, preferablywithin a temperature range between 0° C. and 45° C., especially 5° C. to35° C., and also cures under these conditions.

On application, the crosslinking reaction of the silane groupscommences, if appropriate under the influence of moisture. Silane groupspresent can condense with silanol groups present to give siloxane groups(Si—O—Si groups).

Silane groups present can also be hydrolyzed on contact with moisture togive silanol groups (Si—OH groups) and form siloxane groups (Si—O—Sigroups) through subsequent condensation reactions. As a result of thesereactions, the composition ultimately cures. The amidine of the formula(I) accelerates this curing.

If water is required for the curing, this can either come from the air(air humidity), or else the composition can be contacted with awater-containing component, for example by painting, for example with asmoothing agent, or by spraying, or water or a water-containingcomponent can be added to the composition on application, for example inthe form of a water-containing or water-releasing liquid or paste. Apaste is especially suitable if the composition itself is in the form ofa paste.

In the case of curing by means of air humidity, the composition curesfrom the outside inward, at first forming a skin on the surface of thecomposition. What is called the skin time is a measure of the curingrate of the composition. The speed of curing is generally determined byvarious factors, for example the availability of water, temperature,etc.

The composition is suitable for a multitude of uses, especially as apaint, varnish or primer, as a resin for production of fiber composites,as a rigid foam, flexible foam, molding, elastomer, fiber, film ormembrane, as a potting compound, sealant, adhesive, covering, coating orpaint for construction and industrial applications, for example as aseam seal, cavity seal, electrical insulation compound, spacklingcompound, joint sealant, weld or crimp seam sealant, assembly adhesive,bodywork adhesive, glazing adhesive, sandwich element adhesive,laminating adhesive, laminate adhesive, packaging adhesive, woodadhesive, parquet adhesive, anchoring adhesive, floor covering, floorcoating, balcony coating, roof coating, concrete protection coating,parking garage coating, seal, pipe coating, anticorrosion coating,textile coating, damping element, sealing element or spackling compound.

The composition is particularly suitable as an adhesive and/or sealant,especially for joint sealing and for elastic adhesive bonds inconstruction and industrial applications, and as elastic coating withcrack-bridging properties, especially for protection and/or sealing of,for example, roofs, floors, balconies, parking decks or concrete pipes.

The composition is thus preferably an adhesive or a sealant or acoating.

A composition of this kind typically comprises plasticizers, fillers,adhesion promoters and/or crosslinkers and desiccants, and optionallyfurther auxiliaries and additives.

For an application as adhesive or sealant, the composition preferablyhas a pasty consistency with structurally viscous properties. Such apasty sealant or adhesive is especially applied to a substrate fromstandard cartridges which are operated manually, by means of compressedair or with a battery, or from a vat or hobbock by means of a deliverypump or an extruder, optionally by means of an application robot.

For an application as coating, the composition preferably has a liquidconsistency at room temperature with self-leveling properties. It may beslightly thixotropic, such that the coating is applicable to sloping tovertical surfaces without flowing away immediately. It is especiallyapplied by means of a roller or brush or by pouring-out and distributionby means, for example, of a roller, a scraper or a notched trowel.

On application, the composition is preferably applied to at least onesubstrate. Suitable substrates are especially

-   -   glass, glass ceramic, concrete, mortar, brick, tile, gypsum and        natural rocks such as limestone, granite or marble;    -   metals or alloys such as aluminum, iron, steel and nonferrous        metals, and also surface-finished metals or alloys such as        galvanized or chromed metals;    -   leather, textiles, paper, wood, woodbase materials bonded with        resins, for example phenolic, melamine or epoxy resins,        resin-textile composites and further polymer composites;    -   plastics such as polyvinyl chloride (rigid and flexible PVC),        acrylonitrile-butadiene-styrene copolymers (ABS), polycarbonate        (PC), polyamide (PA), polyesters, poly(methyl methacrylate)        (PMMA), epoxy resins, polyurethanes (PUR), polyoxymethylene        (POM), polyolefins (PO), polyethylene (PE) or polypropylene        (PP), ethylene/propylene copolymers (EPM) and        ethylene/propylene/diene terpolymers (EPDM), and also        fiber-reinforced plastics such as carbon fiber-reinforced        plastics (CFP), glass fiber-reinforced plastics (GFP) and sheet        molding compounds (SMC), where the plastics may preferably have        been surface-treated by means of plasma, corona or flames;    -   coated substrates such as powder-coated metals or alloys;    -   paints or varnishes, especially automotive topcoats.

If required, the substrates can be pretreated prior to the applicationof the composition, especially by chemical and/or physical cleaningmethods or by the application of an adhesion promoter, an adhesionpromoter solution or a primer.

The composition is particularly suitable for contact with substratesthat are particularly sensitive to defects caused by migratingsubstances, especially by the formation of discoloration or specks.These are, in particular, fine-pore substrates such as marble, limestoneor other natural stones, gypsum, cement mortar or concrete, but alsoplastics. Especially on PVC, severe discoloration is observed in thepresence of catalysts, for example DBU or TMG, and cannot be removed bycleaning. No such effects are observed with the amidine of the formula(I).

It is possible to bond or seal two identical or two differentsubstrates, especially the aforementioned substrates.

After the curing of the composition with water, especially in the formof air humidity, and/or with at least one suitable crosslinker, a curedcomposition is obtained.

The use of the composition gives rise to an article which especially hasbeen bonded, sealed or coated with the composition. The article isespecially a built structure, especially a structure built by structuralengineering or civil engineering, an industrially manufactured good or aconsumable good, especially a window, a domestic appliance or a mode oftransport such as, more particularly, an automobile, a bus, a truck, arail vehicle, a ship, an aircraft or a helicopter; or the article may bean installable component thereof.

EXAMPLES

Adduced hereinafter are working examples which are intended to elucidatethe invention described in detail. It will be appreciated that theinvention is not restricted to these described working examples.

“Standard climatic conditions” refer to a temperature of 23±1° C. and arelative air humidity of 50±5%.

“EEW” stands for epoxy equivalent weight.

¹H NMR spectra were measured on a spectrometer of the Bruker Ascend 400type at 400.14 MHz; the chemical shifts δ are reported in ppm relativeto tetramethylsilane (TMS). Coupling constants J are reported in Hz. Nodistinction was made between true coupling and pseudo-coupling patterns.

Infrared spectra (FT-IR) were measured on a Nicolet iS5 FT-IR instrumentfrom Thermo Scientific equipped with a horizontal ATR measurement unitwith a diamond crystal. Liquid samples were applied undiluted as films;solid samples were dissolved in CH₂Cl₂. The absorption bands arereported in wavenumbers (cm⁻¹) (measurement window: 4000-650 cm⁻¹).

The skin time (ST) was determined by applying a few grams of thecomposition to cardboard in a layer thickness of about 2 mm andmeasuring, under standard climatic conditions, the time until, when thesurface of the composition was gently tapped by means of an LDPEpipette, there were for the first time no residues remaining any longeron the pipette.

The characteristics of the surface were tested by touch.

The mechanical properties of tensile strength, elongation at break andmodulus of elasticity (at 0-5% and at 0-50% or 0-100% elongation) weremeasured in accordance with DIN EN 53504 at a pulling speed of 200mm/min.

Functional Compounds Used:

-   PGE phenyl glycidyl ether (from Sigma-Aldrich)-   GLYEO 3-glycidoxypropyltriethoxysilane (Dynasylan® GLYEO, from    Evonik)-   TBA tert-butyl acrylate (from Sigma-Aldrich)-   THFMA tetrahydrofurfuryl methacrylate (from Sigma-Aldrich)-   TMPTA 1,1,1-trimethylolpropane triacrylate (SR-351, from Sartomer)-   Y-9936 3-methacryloyloxypropyltriethoxysilane (Silquest® Y-9936,    from Momentive)-   NAM 4-acryloylmorpholine (from Sigma-Aldrich)-   DEM diethyl maleate (from Sigma-Aldrich)

Preparation of Amidines of the Formula HZ Amidine HZ-1: 2-Methyl-11,4,5,6-tetrahydropyrimidine

In a round-bottom flask, 7.58 g of propane-1,3-diamine, 16.37 g oftrimethyl orthoacetate and 0.60 g of lanthanum(III)trifluoromethanesulfonate were mixed and the mixture was heated to 100°C. while stirring for 24 hours. Thereafter, the reaction mixture wasfreed of the volatile constituents under reduced pressure.

This gave 5.97 g of a white solid.

¹H NMR (CDCl₃): δ 1.75 (quint, 2H, J=5.8, NCH₂CH₂CH₂N), 1.83 (s, 3H,CH₃), 3.30 (t, 4H, J=5.8, NCH₂).

FT-IR: 3214, 3177, 2996, 2925, 2843, 1630, 1542, 1475, 1438, 1380, 1360,1322, 1294, 1273, 1204, 1191, 1139, 1114, 1095, 1035, 1009, 977, 915,875, 839, 731.

Preparation of Amidines of the Formula (I) Amidine K-1:1-(2-Hydroxy-3-phenoxyprop-1-yl)-2-methyl-1,4,5,6-tetrahydropyrimidine

In a round-bottom flask, 1.26 g of amidine HZ-1 were mixed with 1.93 gof PGE and heated to 80° C. for 3 hours. This gave an odorless, yellowoil of high viscosity.

FT-IR: 3060, 2925, 2852, 2714, 1598, 1586, 1494, 1430, 1379, 1359, 1316,1299, 1241, 1172, 1153, 1077, 1036, 1020, 951, 918, 881, 814, 751, 690.

Amidine K-2:1-(2-Hydroxy-3-(3-triethoxysilylpropoxy)prop-1-yl)-2-methyl-1,4,5,6-tetrahydropyrimidine

In a round-bottom flask, 1.55 g of amidine HZ-1 were mixed with 4.21 gof GLYEO and heated to 100° C. until, after 3.5 hours, no GLYEO wasdetectable any longer by means of gas chromatography. This gave anodorless yellow oil. ¹H NMR (CDCl₃): δ 0.62 (br m, 2H, CH₂Si), 1.20 (t,9H, J=6.8, CH₂CH₃), 1.6-1.75 (m, 2H, CH₂CH₂Si), 1.77-1.85 (m, 2H,NCH₂CH₂CH₂N), 1.99 (s, 3H, N═CCH₃), 3.22-3.3 (m, 6H, CH₂N), 3.3-3.5 und3.65 (m, 4H, CH₂OCH₂), 3.81 (q, 6H, J=6.9, SiOCH₂), 4.16 (br m, 1H,CHOH).

FT-IR: 2971, 2925, 2882, 2863, 1615, 1550, 1482, 1433, 1379, 1318, 1294,1261, 1194, 1164, 1100, 1074, 1031, 951, 880, 850, 772, 655.

Amidine K-3: tert-Butyl3-(2-methyl-1,4,5,6-tetrahydropyrimidin-1-yl)propionate

In a round-bottom flask, 2.20 g of amidine HZ-1 were mixed with 2.72 gof TBA and heated to 100° C. until, after 5 hours, no TBA was detectableany longer by means of gas chromatography. Thereafter, the reactionmixture was freed of the volatile constituents under reduced pressure.This gave an odorless yellow oil.

¹H NMR (CDCl₃): δ 1.47 (s, 9H, C(CH₃)₃), 1.81 (t, 2H, J=5.8,NCH₂CH₂CH₂N), 1.99 (s, 3H, N═CCH₃), 2.44 (t, 2H, J=7.3, CH₂C═O), 3.17(t, 2H, J=5.9, NCH₂ ^(Cy)), 3.27-3.32 (m, 2H, NCH₂ ^(Cy)), 3.45 (t, 2H,J=7.2, NCH₂CH₂C═O).

FT-IR: 3220, 2974, 2929, 2848, 1723, 1669, 1618, 1551, 1422, 1366, 1316,1281, 1253, 1211, 1150, 1119, 1083, 1046, 1008, 988, 953, 922, 882, 845,753, 695.

Amidine K-4: Tetrahydrofurfuryl3-(2-methyl-1,4,5,6-tetrahydropyrimidin-1-yl)-2-methylpropionate

In a round-bottom flask, 2.03 g of amidine HZ-1 were mixed with 3.36 gof THFMA and heated to 100° C. until, after 5 hours, no THFMA wasdetectable any longer by means of gas chromatography. Thereafter, thereaction mixture was freed of the volatile constituents under reducedpressure. This gave an odorless orange oil.

FT-IR: 3292, 2930, 2860, 1732, 1696, 1638, 1615, 1564, 1496, 1440, 1377,1361, 1319, 1287, 1259, 1208, 1173, 1140, 1068, 1031, 986, 952, 919,885, 841, 814, 724, 688.

Amidine K-5: Reaction mixture comprising 1,1,1-trimethylolpropanebis(3-(2-methyl-1 1,4,5,6-tetrahydropyrimidin-1-yl)propionate) acrylate

In a round-bottom flask, 2.45 g of amidine HZ-1, 3.56 g of TMPTA and 10mL of tetrahydrofuran were mixed and heated to 80° C. until, after 24hours, no TMPTA was detectable any longer by means of gaschromatography.

Thereafter, the reaction mixture was freed of the volatile constituentsunder reduced pressure. This gave an odorless, yellow oil of highviscosity.

FT-IR: 3258, 2928, 2853, 1729, 2696, 1637, 1613, 1554, 1494, 1443, 1382,1319, 1284, 1206, 1171, 1119, 1048, 1030, 992, 949, 914, 885, 852, 841,778, 713, 686.

Amidine K-6: 3-Triethoxysilylpropyl3-(2-methyl-1,4,5,6-tetrahydropyrimidin-1-yl)-2-methylpropionate

In a round-bottom flask, 1.97 g of amidine HZ-1, 5.15 g of Y-9936 and 8ml of tetrahydrofuran were mixed and heated to 90° C. for 6 hours.Thereafter, the reaction mixture was freed of the volatile constituentsunder reduced pressure.

This gave an odorless yellow oil.

FT-IR: 3180, 2971, 2927, 2883, 1731, 1720, 1637, 1619, 1566, 1497, 1440,1383, 1319, 1295, 1254, 1166, 1075, 1018, 951, 886, 841, 765, 690.

Amidine K-7:3-(2-Methyl-1,4,5,6-tetrahydropyrimidin-1-yl)-1-morpholinopropan-1-one

In a round-bottom flask, 1.16 g of amidine HZ-1 and 1.68 g of NAM weremixed and heated to 80° C. for 4 hours. This gave an odorless yellow oilwhich solidified when left to stand at room temperature.

¹H NMR (CDCl₃): δ 1.80-1.87 (m, 2H, NCH₂CH₂CH₂N), 2.01 (s, 3H, CH₃),2.53 (t, 2H, J=7.3, CH₂C═O), 3.16-3.32 and 3.27-3.34 (2×m, 2×2 H,NCH₂CH₂CH₂N), 3.44-3.5 (m, 2H, CH₂N^(morpholine)), 3.53 (t, 2H, J=7.5,NCH₂CH₂C═O), 3.6-3.65 (m, 2H, CH₂N^(morpholine)), 3.66-3.7 (m, 4H,CH₂O).

FT-IR: 3177, 2924, 2851, 1611, 1424, 1380, 1358, 1316, 1298, 1270, 1230,1214, 1113, 1085, 1068, 1025, 1008, 982, 845, 915, 882, 847, 790, 720.

Amidine K-8: Diethyl2-(2-methyl-1,4,5,6-tetrahydropyrimidin-1-yl)succinate

In a round-bottom flask, 1.84 g of amidine HZ-1 and 3.28 g of DEM weremixed and heated to 60° C. until, after 1 hour, no DEM was detectableany longer by means of thin-layer chromatography. This gave an odorlessorange oil.

FT-IR: 3221, 2979, 2933, 2853, 1729, 1674, 1625, 1568, 1502, 1475, 1442,1414, 1393, 1361, 1295, 1269, 1156, 1096, 1026, 974, 957, 882, 824, 792,777, 735, 690.

Preparation of Polyethers Containing Silane Groups Polymer STP-1

With exclusion of moisture, 1000 g of Acclaim® 12200 polyol(polyoxypropylenediol having a low level of unsaturation, from Bayer; OHnumber 11.0 mg KOH/g), 43.6 g of isophorone diisocyanate (IPDI;Vestanat® IPDI, from Evonik), 126.4 g of diisodecyl phthalate (DIDP) and0.1 g of bismuth tris(neodecanoate) (10% by weight in DIDP) were heatedup to 90° C. while stirring constantly and left at this temperatureuntil the content of free isocyanate groups determined by titrimetry hadreached a stable value of 0.63% by weight. Subsequently, 63.0 g ofdiethyl N-(3-trimethoxysilylpropyl)-aminosuccinate (adduct formed from3-aminopropyltrimethoxysilane and diethyl maleate; prepared according tothe details in U.S. Pat. No. 5,364,955) were mixed in and the mixturewas stirred at 90° C. until it was no longer possible to detect any freeisocyanate by means of FT-IR spectroscopy. The polyether containingtrimethoxysilane groups thus obtained, having a silane equivalent weightof about 6880 g/eq (calculated from the amounts used), was cooled downto room temperature and stored with exclusion of moisture.

Commercial Catalysts Used:

DBU 1,8-diazabicyclo[5.4.0]undec-7-ene (Lupragen® N 700, from BASF)

TMG 1,1,3,3-tetramethylguanidine (from Sigma-Aldrich)

Compositions Based on Polymers Containing Silane Groups:

Comparative examples in tables 1 to 4 are indicated by “(Ref)”.

Compositions Z1 to Z10:

A composition composed of 96.5 g of polymer STP-1, 0.5 g ofvinyltrimethoxysilane and 3.0 g of 3-aminopropyltrimethoxysilane wasblended with various catalysts in the amount specified according totable 1, and the mixture was tested for viscosity and skin time (ST)under standard climatic conditions, before and after storage. The skintime serves as a measure of the activity of the catalyst in relation tothe crosslinking reaction of the silane groups, i.e. of the crosslinkingrate; the change in viscosity and the skin time after storage are ameasure of storage stability. In addition, the mixture applied, after 24hours under standard climatic conditions, was tested as to whether thesurface was dry as desired or whether a greasy film had formed, which isa sign of the exudation of the catalyst owing to poor compatibility withthe cured polymer, and/or whether the surface was tacky, which is a signof incomplete curing. In addition, the mixture was used to produce afilm of thickness 2 mm, which was left to cure under standard climaticconditions for 7 days and tested for mechanical properties. The resultsare shown in tables 1 and 2. “Comp.” stands for “composition”.

TABLE 1 Viscosity [Pa · s] ST Comp. Catalyst Amount Concentration¹ freshstored² increase fresh stored² Z1 Amidine K-1³ 0.46 g 1.9 29.2 30.5  4%20′ 24′ Z2 Amidine K-2 0.69 g 1.9 22.0 28.3 29% 27′ 29′ Z3 Amidine K-30.41 g 1.9 21.3 25.5 20% 29′ 32′ Z4 Amidine K-4 0.49 g 1.9 21.9 29.1 33%30′ 42′ Z5 Amidine K-5 0.48 g 1.9 30.6 35.4 16% 53′ 54′ Z6 Amidine K-60.71 g 1.9 29.3 32.1 10% 28′ 29′ Z7 Amidine K-7³ 0.44 g 1.9 30.0 38.027% 25′ 21′ Z8 Amidine K-8 0.50 g 1.9 30.3 34.5 14% 29′ 30′ Z9 (ref.)DBU 0.28 g 1.9 27.2 36.9 36% 25′ 29′ Z10 (ref.) TMG 0.21 g 1.9 22.3 24.610% 65′ 75′ ¹mmol of amidine or guanidine groups per 100 g of polyethercontaining silane groups. ²for 7 days at 60° C. in a closed container.³as a solution (30% by wt.) in N-ethylpyrrolidone.

TABLE 2 Surface Tensile Elongation Modulus of elasticity Comp. after 24h strength at break 0-5% 0-50% Z1 dry 0.67 MPa 89% 1.29 MPa 0.82 MPa Z2almost dry 0.71 MPa 100%  1.23 MPa 0.82 MPa Z3 almost dry 0.68 MPa 95%1.25 MPa 0.80 MPa Z4 almost dry 0.73 MPa 110%  1.25 MPa 0.79 MPa Z5 dry0.78 MPa 126%  1.21 MPa 0.79 MPa Z6 dry 0.82 MPa 99% 1.26 MPa 0.83 MPaZ7 dry 0.69 MPa 88% 1.22 MPa 0.81 MPa Z8 dry 0.70 MPa 95% 1.17 MPa 0.82MPa Z9 (ref.) greasy 0.58 MPa 72% 1.16 MPa 0.77 MPa Z10 (ref.) tacky0.62 MPa 90% 1.19 MPa 0.75 MPa

Compositions Z11 and Z12

In a round-bottom flask, 71.1 g of an OH-terminated linearpolydimethylsiloxane having a viscosity of about 50,000 mPas at 23° C.(Wacker® Silicone Rubber Polymer FD 50, from Wacker) were blended with2.6 g of vinyltris(methylethylketoximo)silane and mixed under reducedpressure for 15 minutes. 26.3 g of trimethylsilyl-terminatedpolydimethylsiloxane (Wacker® AK 100 silicone oil, from Wacker) werestirred into the polydimethylsiloxane havingvinylbis(methylethylketoximo)silyl end groups that was obtained in thisway. This mixture was blended with various catalysts according to table3 below and, as described for composition Z1, tested for viscosity, skintime (ST), surface characteristics and mechanical properties. Theresults are shown in tables 3 and 4. “Comp.” stands for “composition”.

TABLE 3 Viscosity [Pa · s] ST Comp. Catalyst Amount Concentration¹ freshstored² increase fresh stored² Z11 Amidine K-2 0.15 g 0.6 13.1 9.6 −27%23′ 27′ Z12 (ref.) DBU 0.06 g 0.6 13.0 10.2 −22% 13′ 14′ ¹mmol ofamidine groups per 100 g of ketoximato-polydimethylsiloxane polymer.²for 7 days at 70° C. in a closed container.

TABLE 4 Surface Tensile Elongation Modulus of elasticity Comp. after 24h strength at break 0-5% 0-50% Z11 dry 0.18 MPa 240% 0.20 MPa 0.11 MPaZ12 (ref.) almost dry 0.25 MPa 289% 0.22 MPa 0.16 MPa

The invention claimed is:
 1. An amidine of the formula (I)

wherein p is 1 and r is 0, L is a monovalent hydrocarbyl radical having1 to 6 carbon atoms and containing an alkoxysilane group, Q is aglycidoxy group, Q′ is a divalent connecting unit formed from thereaction of a reactive Q group with HZ, and Z is an aliphatic amidinegroup bonded via a nitrogen atom.
 2. An amidine as claimed in claim 1,wherein Q′ is


3. An amidine as claimed in claim 1, wherein said amidine is of formula(I′):

wherein E⁵ is an alkylene radical having 1 to 6 carbon atoms, E⁶ is analkyl radical having 1 to 4 carbon atoms, u is 0 or 1, and v is 2 or 3,with the proviso that (u+v) equals 3, and Z is an aliphatic amidinegroup bonded via a nitrogen atom.
 4. An amidine as claimed in claim 1,wherein L is triethoxysilylpropyl or trimethoxysilylpropyl.
 5. Anamidine as claimed in claim 1, wherein Z is

wherein R¹ is a hydrogen radical or an alkyl or cycloalkyl or aralkylradical having 1 to 8 carbon atoms or together with R² is R⁴, R² is ahydrogen radical or an alkyl, cycloalkyl or aralkyl radical which has 1to 18 carbon atoms and optionally contains ether oxygen or tertiaryamine nitrogen, or together with R¹ is R⁴, R³ is a hydrogen radical oran alkyl or cycloalkyl or aralkyl radical having 1 to 12 carbon atoms,wherein R⁴ is an optionally substituted 1,2-ethylene, 1,3-propylene or1,4-butylene radical having 2 to 12 carbon atoms, and wherein R² and R³together may also be an alkylene radical having 3 to 6 carbon atoms. 6.An amidine as claimed in claim 5 wherein R¹ and R² together are R⁴.
 7. Aprocess for preparing the amidine of the formula (I) as claimed in claim1, wherein at least one amidine of the formula HZ is reacted with atleast one functional compound of the formula L

Q]_((p+r)) wherein p is 1 and r is 0, L is a monovalent hydrocarbylradical having 1 to 6 carbon atoms and containing an alkoxysilane group,and Q is a glycidoxy group.
 8. The process as claimed in claim 7,wherein the amidine of the formula HZ has the formula

wherein R³ is a hydrogen radical or an alkyl or cycloalkyl or aralkylradical having 1 to 12 carbon atoms, and R⁴ is an optionally substituted1,2-ethylene, 1,3-propylene or 1,4-butylene radical having 2 to 12carbon atoms.
 9. A method comprising applying as catalyst for thecrosslinking of a curable composition the amidine of the formula (I) asclaimed in claim
 1. 10. A method as claimed in claim 9, wherein thecurable composition is an epoxy resin composition or a polyurethanecomposition or an epoxy resin/polyurethane composition or a cyanateester resin composition or a composition containing silane groups.
 11. Amethod as claimed claim 10, wherein the curable composition is acomposition based on polymers containing silane groups selected from thegroup consisting of polyorganosiloxanes having terminal silane groupsand organic polymers containing silane groups.
 12. A method as claimedin claim 9, wherein the curable composition is a polyurethanecomposition or a composition containing silane groups.
 13. A curablecomposition comprising at least one amidine of the formula (I) asclaimed in claim
 1. 14. The composition as claimed in claim 13, whereinit further comprises at least one polymer containing silane groups. 15.The composition as claimed in claim 13, wherein it is an adhesive or asealant or a coating.